Patent Publication Number: US-6669595-B1

Title: Planetary transmissions with a stationary member and clutched input

Description:
TECHNICAL FIELD 
     The present invention relates to a family of power transmissions having three planetary gear sets that are controlled by six torque-transmitting devices to provide at least seven forward speed ratios and one reverse speed ratio. 
     BACKGROUND OF THE INVENTION 
     Passenger vehicles include a powertrain that is comprised of an engine, multi-speed transmission, and a differential or final drive. The multi-speed transmission increases the overall operating range of the vehicle by permitting the engine to operate through its torque range a number of times. The number of forward speed ratios that are available in the transmission determines the number of times the engine torque range is repeated. Early automatic transmissions had two speed ranges. This severely limited the overall speed range of the vehicle and therefore required a relatively large engine that could produce a wide speed and torque range. This resulted in the engine operating at a specific fuel consumption point during cruising, other than the most efficient point. Therefore, manually-shifted (countershaft transmissions) were the most popular. 
     With the advent of three- and four-speed automatic transmissions, the automatic shifting (planetary gear) transmission increased in popularity with the motoring public. These transmissions improved the operating performance and fuel economy of the vehicle. The increased number of speed ratios reduces the step size between ratios and therefore improves the shift quality of the transmission by making the ratio interchanges substantially imperceptible to the operator under normal vehicle acceleration. 
     It has been suggested that the number of forward speed ratios be increased to six or more. Six-speed transmissions are disclosed in U.S. Pat. No. 4,070,927 issued to Polak on Jan. 31, 1978; U.S. Pat. No. 6,071,208 issued to Koivunen on Jun. 6, 2000; U.S. Pat. No. 5,106,352 issued to Lepelletier on Apr. 21, 1992; and U.S. Pat. No. 5,599,251 issued to Beim and McCarrick on Feb. 4, 1997. 
     Six-speed transmissions offer several advantages over four- and five-speed transmissions, including improved vehicle acceleration and improved fuel economy. While many trucks employ power transmissions, such as Polak, having six or more forward speed ratios, passenger cars are still manufactured with three- and four-speed automatic transmissions and relatively few five or six-speed devices due to the size and complexity of these transmissions. The Polak transmission provides six forward speed ratios with three planetary gear sets, two clutches, and three brakes. The Koivunen and Beim patents utilize six torque-transmitting devices including four brakes and two clutches to establish six forward speed ratios and a reverse ratio. The Lepelletier patent employs three planetary gear sets, three clutches and two brakes to provide six forward speeds. One of the planetary gear sets is positioned and operated to establish two fixed speed input members for the remaining two planetary gear sets. 
     Seven-speed transmissions are disclosed in U.S. Pat. No. 4,709,594 to Maeda; U.S. Pat. No. 6,053,839 to Baldwin et. al.; and U.S. Pat. No. 6,083,135 to Baldwin et. al. Seven- and eight-speed transmissions provide further improvements in acceleration and fuel economy over six-speed transmissions. However, like the six-speed transmissions discussed above, the development of seven- and eight-speed transmissions has been precluded because of complexity, size and cost. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved family of transmissions having three planetary gear sets controlled to provide at least seven forward speed ratios and one reverse speed ratio. 
     In one aspect of the present invention, the family of transmissions has three planetary gear sets, each of which includes a first, second and third member, which members may comprise a sun gear, a ring gear, or a planet carrier assembly member. 
     In referring to the first, second and third gear sets in this description and in the claims, these sets may be counted “first” to “third” in any order in the drawings (i.e., left to right, right to left, etc.). 
     In another aspect of the present invention, each of the planetary gear sets may be of the single pinion-type or of the double pinion-type. 
     In yet another aspect of the present invention, the first member of the first planetary gear set is continuously interconnected with the first member of the second planetary gear set through a first interconnecting member. 
     In yet another aspect of the present invention, the second member of the first planetary gear set is continuously interconnected with the second member of the second planetary gear set through a second interconnecting member. 
     In yet another aspect of the present invention, the first member of the third planetary gear set is continuously connected with a stationary member. 
     In yet a further aspect of the invention, each family member incorporates an output shaft which is continuously connected with at least one member of the planetary gear sets and an input shaft which is not continuously connected with any member of the planetary gear sets. 
     In a further aspect of the invention, a first torque-transmitting mechanism, such as a clutch, selectively interconnects the input shaft with a member of the first, second or third planetary gear set. 
     In still a further aspect of the invention, a second torque-transmitting mechanism, such as a clutch, selectively interconnects the input shaft with a member of the first, second or third planetary gear set, or with the first or second interconnecting member. 
     In another aspect of the invention, a third torque-transmitting mechanism, such as a clutch, selectively interconnects a member of the first, second or third planetary gear set with the input shaft, or another member of the first, second or third planetary gear set. 
     In a still further aspect of the invention, a fourth torque-transmitting mechanism, such as a clutch, selectively interconnects a member of the first, second or third planetary gear set or the first or second interconnecting member with another member of the first, second or third planetary gear set. 
     In a still further aspect of the invention, a fifth torque-transmitting mechanism, such as a clutch, selectively interconnects a member of the first, second or third planetary gear set with another member of the first, second or third planetary gear set. Alternatively, the fifth torque-transmitting mechanism, such as a brake, selectively interconnects a member of the first, second or third planetary gear set with a stationary member (transmission housing). 
     In still another aspect of the invention, a sixth torque-transmitting mechanism, such as a clutch, selectively interconnects a member of the first, second or third planetary gear set with another member of the first, second or third planetary gear set. Alternatively, the sixth torque transmitting mechanism, such as a brake, selectively connects a member of the first, second or third planetary gear set with the stationary member. 
     In still another aspect of the invention, the six torque-transmitting mechanisms are selectively engageable in combinations of three. to yield at least seven forward speed ratios and one reverse speed ratio. 
     The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 a  is a schematic representation of a powertrain including a planetary transmission incorporating a family member of the present invention; 
     FIG. 1 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 1 a;    
     FIG. 2 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 2 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 2 a;    
     FIG. 3 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 3 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 3 a;    
     FIG. 4 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 4 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 4 a;    
     FIG. 5 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 5 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 5 a;    
     FIG. 6 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 6 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 6 a;    
     FIG. 7 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 7 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 7 a;    
     FIG. 8 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 8 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 8 a;    
     FIG. 9 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 9 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 9 a;    
     FIG. 10 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 10 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 10 a;    
     FIG. 11 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 11 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 11 a;    
     FIG. 12 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; 
     FIG. 12 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 12 a;    
     FIG. 13 a  is a schematic representation of a powertrain having a planetary transmission incorporating another family member of the present invention; and 
     FIG. 13 b  is a truth table and chart depicting some of the operating characteristics of the powertrain shown in FIG. 13 a.   
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, wherein like characters represent the same or corresponding parts throughout the several views, there is shown in FIG. 1 a  a powertrain  10  having a conventional engine and torque converter  12 , a planetary transmission  14 , and a conventional final drive mechanism  16 . 
     The planetary transmission  14  includes an input shaft  17  continuously connected with the engine and torque converter  12 , a planetary gear arrangement  18 , and an output shaft  19  continuously connected with the final drive mechanism  16 . The planetary gear arrangement  18  includes three planetary gear sets  20 ,  30  and  40 . 
     The planetary gear set  20  includes a sun gear member  22 , a ring gear member  24 , and a planet carrier assembly  26 . The planet carrier assembly  26  includes a plurality of pinion gears  27  rotatably mounted on a carrier member  29  and disposed in meshing relationship with both the sun gear member  22  and the ring gear member  24 . 
     The planetary gear set  30  includes a sun gear member  32 , a ring gear member  34 , and a planet carrier assembly member  36 . The planet carrier assembly member  36  includes a plurality of pinion gears  37  rotatably mounted on a carrier member  39  and disposed in meshing relationship with both the sun gear member  32  and the ring gear member  34 . 
     The planetary gear set  40  includes a sun gear member  42 , a ring gear member  44 , and a planet carrier assembly member  46 . The planet carrier assembly member  46  includes a plurality of pinion gears  47  rotatably mounted on a carrier member  49  and disposed in meshing relationship with both the sun gear member  42  and the ring gear member  44 . 
     The planetary gear arrangement also includes six torque-transmitting mechanisms  50 ,  52 ,  54 ,  56 ,  58  and  59 . The torque-transmitting mechanisms  50 ,  52 ,  54  and  56  are rotating-type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanisms  58  and  59  are stationary-type torque-transmitting mechanisms, commonly termed brakes or reaction clutches. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the ring gear member  34 . The ring gear member  44  is continuously connected with the transmission housing  60 . The ring gear member  24  is continuously connected with the sun gear member  32  through the interconnecting member  70 . The planet carrier assembly member  26  is continuously connected with the planet carrier assembly member  36  through the interconnecting member  72 . 
     The input shaft  17  is selectively connectable with the planet carrier assembly member  26  through the clutch  50 . The input shaft  17  is selectively connectable with the sun gear member  42  through the clutch  52 . The planet carrier assembly member  46  is selectively connectable with the ring gear member  24  through the clutch  54 . The sun gear member  42  is selectively connectable with the sun gear member  22  through the clutch  56 . The ring gear member  24  is selectively connectable with the transmission housing  60  through the brake  58 . The planet carrier assembly member  36  is selectively connectable with the transmission housing  60  through the brake  59 . 
     As shown in FIG. 1 b , and in particular the truth table disclosed therein, the torque-transmitting mechanisms are selectively engaged in combinations of three to provide seven forward speed ratios and a reverse speed ratio. It should also be noted in the truth table that the torque-transmitting mechanisms  52  and  59  remain engaged through a neutral condition, thereby simplifying the forward/reverse interchange. 
     The reverse speed ratio is established with the engagement of the clutches  52 ,  54  and the brake  59 . The clutch  52  connects the input shaft  17  with the sun gear member  42 . The clutch  54  connects the sun gear member  32  with the planet carrier assembly member  46 . The brake  59  connects the planet carrier assembly member  36  with the transmission housing  60 . The planet carrier assembly members  26  and  36  do not rotate. The ring gear member  24  rotates at the same speed as the sun gear member  32  and the planet carrier assembly member  46 . The ring gear member  34  rotates at the same speed as the output shaft  19 . The ring gear member  34 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the sun gear member  32  and the ring gear/sun gear tooth ratio of the planetary gear set  30 . The ring gear member  44  does not rotate. The sun gear member  42  rotates at the same speed as the input shaft  17 . The planet carrier assembly member  46  rotates at a speed determined from the speed of the sun gear member  42  and the ring gear/sun gear tooth ratio of the planetary gear set  40 . The numerical value of the reverse speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  30  and  40 . 
     The first forward speed ratio is established with the engagement of the clutches  52 ,  56  and the brake  59 . The clutch  52  connects the input shaft  17  with the sun gear member  42 . The clutch  56  connects the sun gear member  22  with the sun gear member  42 . The brake  59  connects the planet carrier assembly member  36  with the transmission housing  60 . The planet carrier assembly members  26  and  36  do not rotate. The ring gear member  24  rotates at the same speed as the sun gear member  32 . The sun gear members  22  and  42  rotate at the same speed as the input shaft  17 . The ring gear member  24  rotates at a speed determined from the speed of the sun gear member  22  and the ring gear/sun gear tooth ratio of the planetary gear set  20 . The ring gear member  34  rotates at the same speed as the output shaft  19 . The ring gear member  34 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the sun gear member  32  and the ring gear/sun gear tooth ratio of the planetary gear set  30 . The ring gear member  44  does not rotate. The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  20  and  30 . 
     The second forward speed ratio is established with the engagement of the clutches  52 ,  56  and the brake  58 . The ring gear member  24  and sun gear member  32  do not rotate. The planet carrier assembly member  26  rotates at the same speed as the planet carrier assembly member  36 . The sun gear members  22  and  42  rotate at the same speed as the input shaft  17 . The planet carrier assembly member  26  rotates at a speed determined from the speed of the sun gear member  22  and the ring gear/sun gear tooth ratio of the planetary gear set  20 . The ring gear member  34  rotates at the same speed as the output shaft  19 . The ring gear member  34 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  36  and the ring gear/sun gear tooth ratio of the planetary gear set  30 . The ring gear member  44  does not rotate. The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  20  and  30 . 
     The third forward speed ratio is established with the engagement of the clutches  52 ,  54  and  56 . The clutch  52  connects the input shaft  17  with the sun gear member  42 . The clutch  54  connects the sun gear member  32  with the planet carrier assembly member  46 . The clutch  56  connects the sun gear member  22  with the sun gear member  42 . The planet carrier assembly member  26  rotates at the same speed as the planet carrier assembly member  36 . The ring gear member  24  rotates at the same speed as the sun gear member  32  and the planet carrier assembly member  46 . The sun gear members  22  and  42  rotate at the same speed as the input shaft  17 . The planet carrier assembly member  26  rotates at a speed determined from the speed of the ring gear member  24 , the speed of the sun gear member  22  and the ring gear/sun gear tooth ratio of the planetary gear set  20 . The ring gear member  34  rotates at the same speed as the output shaft  19 . The ring gear member  34 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  36 , the speed of the sun gear member  32  and the ring gear/sun gear tooth ratio of the planetary gear set  30 . The ring gear member  44  does not rotate. The planet carrier assembly member  46  rotates at a speed determined from the speed of the sun gear member  42  and the ring gear/sun gear tooth ratio of the planetary gear set  40 . The numerical value of the third forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  20 ,  30  and  40 . 
     The fourth forward speed ratio is established with the engagement of the clutches  50 ,  52  and  56 . In this configuration, the input shaft  17  is directly connected to the output shaft  19 . The numerical value of the fourth forward speed ratio is 1. 
     The fifth forward speed ratio is established with the engagement of the clutches  50 ,  54  and  56 . The clutch  50  connects the input shaft  17  with the planet carrier assembly member  26 . The clutch  54  connects the sun gear member  32  with the planet carrier assembly member  46 . The clutch  56  connects the sun gear member  22  with the sun gear member  42 . The planet carrier assembly members  26  and  36  rotate at the same speed as the input shaft  17 . The ring gear member  24  rotates at the same speed as the sun gear member  32  and the planet carrier assembly member  46 . The sun gear member  22  rotates at the same speed as the sun gear member  42 . The ring gear member  24  rotates at a speed determined from the speed of the planet carrier assembly member  26 , the speed of the sun gear member  22  and the ring gear/sun gear tooth ratio of the planetary gear set  20 . The ring gear member  34  rotates at the same speed as the output shaft  19 . The ring gear member  34 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  36 , the speed of the sun gear member  32  and the ring gear/sun gear tooth ratio of the planetary gear set  30 . The ring gear member  44  does not rotate. The planet carrier assembly member  46  rotates at a speed determined from the speed of the sun gear member  42  and the ring gear/sun gear tooth ratio of the planetary gear set  40 . The numerical value of the fifth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  20 ,  30  and  40 . 
     The sixth forward speed ratio is established with the engagement of the clutches  50 ,  52  and  54 . The clutch  50  connects the input shaft  17  with the planet carrier assembly member  26 . The clutch  52  connects the input shaft  17  with the sun gear member  42 . The clutch  54  connects the sun gear member  32  with the planet carrier assembly member  46 . The planet carrier assembly members  26 ,  36  and the sun gear member  42  rotate at the same speed as the input shaft  17 . The ring gear member  24  rotates at the same speed as the sun gear member  32  and the planet carrier assembly member  46 . The ring gear member  34  rotates at the same speed as the output shaft  19 . The ring gear member  34 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  36 , the speed of the sun gear member  32  and the ring gear/sun gear tooth ratio of the planetary gear set  30 . The ring gear member  44  does not rotate. The planet carrier assembly member  46  rotates at a speed determined from the speed of the sun gear member  42  and the ring gear/sun gear tooth ratio of the planetary gear set  40 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  30  and  40 . 
     The seventh forward speed ratio is established with the engagement of the clutches  50 ,  54  and the brake  58 . The clutch  50  connects the input shaft  17  with the planet carrier assembly member  26 . The clutch  54  connects the sun gear member  32  with the planet carrier assembly member  46 . The brake  58  connects the sun gear member  32  with the transmission housing  60 . The ring gear member  24 , the sun gear member  32  and the planetary gear set  40  do not rotate. The planet carrier assembly members  26  and  36  rotate at the same speed as the input shaft  17 . The ring gear member  34  rotates at the same speed as the output shaft  19 . The ring gear member  34 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  36  and the ring gear/sun gear tooth ratio of the planetary gear set  30 . The numerical value of the seventh forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  30 . 
     As set forth above, the engagement schedule for the torque-transmitting mechanisms is shown in the truth table of FIG. 1 b . This truth table also provides an example of speed ratios that are available utilizing the ring gear/sun gear tooth ratios given by way of example in FIG. 1 b . The R1/S1 value is the tooth ratio of the planetary gear set  20 ; the R2/S2 value is the tooth ratio of the planetary gear set  30 ; and the R3/S3 value is the tooth ratio of the planetary gear set  40 . Also, the chart of FIG. 1 b  describes the ratio steps that are attained utilizing the sample of tooth ratios given. For example, the step ratio between the first and second forward speed ratios is 1.88, while the step ratio between the reverse and first forward ratio is −1. 
     FIG. 2 a  shows a powertrain  110  having a conventional engine and torque converter  12 , a planetary transmission  114 , and a conventional final drive mechanism  16 . 
     The planetary transmission  114  includes an input shaft  17  continuously connected with the engine and torque converter  12 , a planetary gear arrangement  118 , and an output shaft  19  continuously connected with the final drive mechanism  16 . The planetary gear arrangement  118  includes three planetary gear sets  120 ,  130  and  140 . 
     The planetary gear set  120  includes a sun gear member  122 , a ring gear member  124 , and a planet carrier assembly  126 . The planet carrier assembly  126  includes a plurality of pinion gears  127  rotatably mounted on a carrier member  129  and disposed in meshing relationship with both the sun gear member  122  and the ring gear member  124 . 
     The planetary gear set  130  includes a sun gear member  132 , a ring gear member  134 , and a planet carrier assembly member  136 . The planet carrier assembly member  136  includes a plurality of pinion gears  137  rotatably mounted on a carrier member  139  and disposed in meshing relationship with both the sun gear member  132  and the ring gear member  134 . 
     The planetary gear set  140  includes a sun gear member  142 , a ring gear member  144 , and a planet carrier assembly member  146 . The planet carrier assembly member  146  includes a plurality of pinion gears  147  rotatably mounted on a carrier member  149  and disposed in meshing relationship with both the sun gear member  142  and the ring gear member  144 . 
     The planetary gear arrangement  118  also includes six torque-transmitting mechanisms  150 ,  152 ,  154 ,  156 ,  158  and  159 . The torque-transmitting mechanisms  150 ,  152 ,  154  and  156  are rotating-type torque-transmitting mechanisms, commonly termed “clutches.” The torque-transmitting mechanisms  158  and  159  are stationary-type torque-transmitting mechanisms, commonly termed brakes or reaction clutches. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the ring gear member  134 . The sun gear member  142  is continuously connected with the transmission housing  160 . The ring gear member  124  is continuously connected with the sun gear member  132  through the interconnecting member  170 . The planet carrier assembly member  126  is continuously connected with the planet carrier assembly member  136  through the interconnecting member  172 . 
     The input shaft  17  is selectively connectable with the sun gear member  122  through the clutch  150 . The input shaft  17  is selectively connectable with the ring gear member  144  through the clutch  152 . The planet carrier assembly member  146  is selectively connectable with the ring gear member  124  through the clutch  154 . The ring gear member  144  is selectively connectable with the planet carrier assembly member  126  through the clutch  156 . The ring gear member  124  is selectively connectable with the transmission housing  160  through the brake  158 . The planet carrier assembly member  136  is selectively connectable with the transmission housing  160  through the brake  159 . 
     The truth table of FIG. 2 b  describes the engagement sequence utilized to provide seven forward speed ratios and a reverse speed ratio in the planetary gear arrangement  118  shown in FIG. 2 a.    
     The reverse speed ratio is established with the engagement of the clutches  152 ,  154  and the brake  159 . The clutch  152  connects the input shaft  17  with the ring gear member  144 . The clutch  154  connects the sun gear member  132  with the planet carrier assembly member  146 . The brake  159  connects the planet carrier assembly member  136  to the transmission housing  160 . The planet carrier assembly members  126  and  136  do not rotate. The ring gear member  124  rotates at the same speed as the sun gear member  132  and the planet carrier assembly member  146 . The ring gear member  134  rotates at the same speed as the output shaft  19 . The ring gear member  134 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the sun gear member  132  and the ring gear/sun gear tooth ratio of the planetary gear set  130 . The ring gear member  144  rotates at the same speed as the input shaft  17 . The sun gear member  142  does not rotate. The planet carrier assembly member  146  rotates at a speed determined from the speed of the ring gear member  144  and the ring gear/sun gear tooth ratio of the planetary gear set  140 . The numerical value of the reverse speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  130  and  140 . 
     The first forward speed ratio is established with the engagement of the clutches  150 ,  156  and the brake  159 . The clutch  150  connects the input shaft  17  with the sun gear member  122 . The clutch  156  connects the planet carrier assembly member  136  with the ring gear member  144 . The brake  159  connects the planet carrier assembly member  136  with the transmission housing  160 . The sun gear member  122  rotates at the same speed as the input shaft  17 . The planet carrier assembly members  126 ,  136  and the planetary gear set  140  do not rotate. The ring gear member  124  rotates at the same speed as the sun gear member  132 . The ring gear member  124  rotates at a speed determined from the speed of the sun gear member  122  and the ring gear/sun gear tooth ratio of the planetary gear set  120 . The ring gear member  134  rotates at the same speed as the output shaft  19 . The ring gear member  134 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the sun gear member  132  and the ring gear/sun gear tooth ratio of the planetary gear set  130 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  120  and  130 . 
     The second forward speed ratio is established with the engagement of the clutches  150 ,  156  and the brake  158 . The clutch  150  connects the sun gear member  122  with the input shaft  17 . The clutch  156  connects the planet carrier assembly member  136  with the ring gear member  144 . The brake  158  connects the sun gear member  132  with the transmission housing  160 . The sun gear member  122  rotates at the same speed as the input shaft  17 . The planet carrier assembly member  126  rotates at the same speed as the planet carrier assembly member  136  and the ring gear member  144 . The ring gear member  124  and sun gear members  132 ,  142  do not rotate. The planet carrier assembly member  126  rotates at a speed determined from the speed of the sun gear member  122  and the ring gear/sun gear tooth ratio of the planetary gear set  120 . The ring gear member  134  rotates at the same speed as the output shaft  19 . The ring gear member  134 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  136  and the ring gear/sun gear tooth ratio of the planetary gear set  130 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  120  and  130 . 
     The third forward speed ratio is established with the engagement of the clutches  150 ,  154  and  156 . The clutch  150  connects the sun gear member  122  with the input shaft  17 . The clutch  154  connects the sun gear member  132  with the planet carrier assembly member  146 . The clutch  156  connects the planet carrier assembly member  136  with the ring gear member  144 . The ring gear member  124  rotates at the same speed as the sun gear member  132  and the planet carrier assembly member  146 . The planet carrier assembly member  126  rotates at the same speed as the planet carrier assembly member  136  and the ring gear member  144 . The sun gear member  122  rotates at the same speed as the input shaft  17 . The planet carrier assembly member  126  rotates at a speed determined from the speed of the ring gear member  124 , the speed of the sun gear member  122  and the ring gear/sun gear tooth ratio of the planetary gear set  120 . The ring gear member  134  rotates at the same speed as the output shaft  19 . The ring gear member  134 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  136 , the speed of the sun gear member  132  and the ring gear/sun gear tooth ratio of the planetary gear set  130 . The sun gear member  142  does not rotate. The planet carrier assembly member  146  rotates at a speed determined from the speed of the ring gear member  144  and the ring gear/sun gear tooth ratio of the planetary gear set  140 . The numerical value of the third forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  120 ,  130  and  140 . 
     The fourth forward speed ratio is established with the engagement of the clutches  150 ,  152  and  154 . The clutch  150  connects the sun gear member  122  with the input shaft  17 . The clutch  152  connects the ring gear member  144  with the input shaft  17 . The clutch  154  connects the sun gear member  132  with the planet carrier assembly member  146 . The ring gear member  124  rotates at the same speed as the sun gear member  132  and the planet carrier assembly member  146 . The planet carrier assembly member  126  rotates at the same speed as the planet carrier assembly member  136 . The sun gear member  122  and ring gear member  144  rotate at the same speed as the input shaft  17 . The planet carrier assembly member  126  rotates at a speed determined from the speed of the ring gear member  124 , the speed of the sun gear member  122  and the ring gear/sun gear tooth ratio of the planetary gear set  120 . The ring gear member  134  rotates at the same speed as the output shaft  19 . The ring gear member  134 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  136 , the speed of the sun gear member  132  and the ring gear/sun gear tooth ratio of the planetary gear set  130 . The sun gear member  142  does not rotate. The planet carrier assembly member  146  rotates at a speed determined from the speed of the ring gear member  144  and the ring gear/sun gear tooth ratio of the planetary gear set  140 . The numerical value of the fourth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  120 ,  130  and  140 . 
     The fifth forward speed ratio is established with the engagement of the clutches  150 ,  152  and  156 . In this configuration, the input shaft  17  is directly connected to the output shaft  19 . The numerical value of the fifth forward speed ratio is 1. 
     The sixth forward speed ratio is established with the engagement of the clutches  152 ,  154  and  156 . The clutch  152  connects the ring gear member  144  with the input shaft  17 . The clutch  154  connects the sun gear member  132  with the planet carrier assembly member  146 . The clutch  156  connects the planet carrier assembly member  136  with the ring gear member  144 . The planet carrier assembly member  126 ,  136  and the ring gear member  144  rotate at the same speed as the input shaft  17 . The ring gear member  124  rotates at the same speed as the sun gear member  132  and the planet carrier assembly member  146 . The ring gear member  134  rotates at the same speed as the output shaft  19 . The ring gear member  134 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  136 , the speed of the sun gear member  132  and the ring gear/sun gear tooth ratio of the planetary gear set  130 . The sun gear member  142  does not rotate. The planet carrier assembly member  146  rotates at a speed determined from the speed of the ring gear member  144  and the ring gear/sun gear tooth ratio of the planetary gear set  140 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  130  and  140 . 
     The seventh forward speed ratio is established with the engagement of the clutches  152 ,  156  and the brake  158 . The clutch  152  connects the ring gear member  144  with the input shaft  17 . The clutch  156  connects the planet carrier assembly member  136  with the ring gear member  144 . The brake  158  connects the sun gear member  132  with the transmission housing  160 . The planet carrier assembly members  126 ,  136  and the ring gear member  144  rotate at the same speed as the input shaft  17 . The ring gear member  124  and sun gear member  132  do not rotate. The ring gear member  134  rotates at the same speed as the output shaft  19 . The ring gear member  134 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  136  and the ring gear/sun gear tooth ratio of the planetary gear set  130 . The sun gear member  142  does not rotate. The numerical value of the seventh forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  130 . 
     As set forth above, the truth table of FIG. 2 b  describes the engagement sequence of the torque-transmitting mechanisms utilized to provide a reverse drive ratio and seven forward speed ratios. It can be readily determined from the truth table that all of the single step forward interchanges are of the single transition type, except for the reverse to first step. The truth table also provides an example of the ratios that can be attained with the family members shown in FIG. 2 a  utilizing the sample tooth ratios given in FIG. 2 b . The R1/S1 value is the tooth ratio of the planetary gear set  120 ; the R2/S2 value is the tooth ratio of the planetary gear set  130 ; and the R3/S3 value is the tooth ratio of the planetary gear set  140 . Also shown in FIG. 2 b  are the ratio steps between single step ratios in the forward direction as well as the reverse to first ratio step ratio. For example, the first to second step ratio is 1.98. 
     Turning to FIG. 3 a , a powertrain  210  includes the engine and torque converter  12 , a planetary transmission  214 , and a final drive mechanism  16 . The planetary transmission  214  includes an input shaft  17  continuously connected with the engine and torque converter  12 , a planetary gear arrangement  218 , and an output shaft  19  continuously connected with the final drive mechanism  16 . The planetary gear arrangement  218  includes three planetary gear sets  220 ,  230  and  240 . 
     The planetary gear set  220  includes a sun gear member  222 , a ring gear member  224 , and a planet carrier assembly  226 . The planet carrier assembly  226  includes a plurality of pinion gears  227  rotatably mounted on a carrier member  229  and disposed in meshing relationship with both the sun gear member  222  and the ring gear member  224 . 
     The planetary gear set  230  includes a sun gear member  232 , a ring gear member  234 , and a planet carrier assembly member  236 . The planet carrier assembly member  236  includes a plurality of pinion gears  237  rotatably mounted on a carrier member  239  and disposed in meshing relationship with both the sun gear member  232  and the ring gear member  234 . 
     The planetary gear set  240  includes a sun gear member  242 , a ring gear member  244 , and a planet carrier assembly member  246 . The planet carrier assembly member  246  includes a plurality of pinion gears  247  rotatably mounted on a carrier member  249  and disposed in meshing relationship with both the sun gear member  242  and the ring gear member  244 . 
     The planetary gear arrangement  218  also includes six torque-transmitting mechanisms  250 ,  252 ,  254 ,  256 ,  258  and  259 . The torque-transmitting mechanisms  250 ,  252 ,  254  and  256  are rotating type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanisms  258  and  259  are stationary type torque-transmitting mechanisms, commonly termed brakes or reaction clutches. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the ring gear member  234 . The sun gear member  242  is continuously connected with the transmission housing  260 . The ring gear member  224  is continuously connected with the sun gear member  232  through the interconnecting member  270 . The planet carrier assembly member  226  is continuously connected with the planet carrier assembly member  236  through the interconnecting member  272 . 
     The input shaft  17  is selectively connectable with the sun gear member  222  through the clutch  250 . The input shaft  17  is selectively connectable with the planet carrier assembly member  246  through the clutch  252 . The planet carrier assembly member  246  is selectively connectable with the ring gear member  224  through the clutch  254 . The ring gear member  244  is selectively connectable with the planet carrier assembly member  226  through the clutch  256 . The ring gear member  224  is selectively connectable with the transmission housing  260  through the brake  258 . The planet carrier assembly member  236  is selectively connectable with the transmission housing  260  through the brake  259 . 
     As shown in the truth table in FIG. 3 b , the torque-transmitting mechanisms are engaged in combinations of three to establish seven forward speed ratios and one reverse ratio. 
     The reverse speed ratio is established with the engagement of the clutches  252 ,  254  and the brake  259 . The clutch  252  connects the input shaft  17  with the planet carrier assembly member  246 . The clutch  254  connects the sun gear member  232  with the planet carrier assembly member  246 . The brake  259  connects the planet carrier assembly member  236  with the transmission housing  260 . The planet carrier assembly members  226  and  236  do not rotate. The ring gear member  224 , sun gear member  232  and planet carrier assembly member  246  rotate at the same speed as the input shaft  17 . The ring gear member  234  rotates at the same speed as the output shaft  19 . The ring gear member  234 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the sun gear member  232  and the ring gear/sun gear tooth ratio of the planetary gear set  230 . The sun gear member  242  does not rotate. The numerical value of the reverse speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  230 . 
     The first forward speed ratio is established with the engagement of the clutches  250 ,  256  and the brake  259 . The clutch  250  connects the input shaft  17  with the sun gear member  222 . The clutch  256  connects the planet carrier assembly member  236  with the ring gear member  244 . The brake  259  connects the planet carrier assembly member  236  with the transmission housing  260 . The planet carrier assembly members  226  and  236  and the planetary gear set  240  do not rotate. The sun gear member  222  rotates at the same speed as the input shaft  17 . The ring gear member  224  rotates at a speed determined from the speed of the sun gear member  232 . The ring gear member  224  rotates at a speed determined from the speed of the sun gear member  222  and the ring gear/sun gear tooth ratio of the planetary gear set  220 . The ring gear member  234  rotates at the same speed as the output shaft  19 . The ring gear member  234 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the sun gear member  232  and the ring gear/sun gear tooth ratio of the planetary gear set  230 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  220  and  230 . 
     The second forward speed ratio is established with the engagement of the clutches  250 ,  256  and the brake  258 . The clutch  250  connects the input shaft  17  with the sun gear member  222 . The clutch  256  connects the planet carrier assembly member  236  with the ring gear member  244 . The brake  258  connects the sun gear member  232  with the transmission housing  260 . The ring gear member  224  and sun gear members  232 ,  242  do not rotate. The planet carrier assembly member  226  rotates at the same speed as the planet carrier assembly member  236  and the ring gear member  244 . The sun gear member  222  rotates at the same speed as the input shaft  17 . The planet carrier assembly member  226  rotates at a speed determined from the speed of the sun gear member  222  and the ring gear/sun gear tooth ratio of the planetary gear set  220 . The ring gear member  234  rotates at the same speed as the output shaft  19 . The ring gear member  234 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  236  and the ring gear/sun gear tooth ratio of the planetary gear set  230 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  220  and  230 . 
     The third forward speed ratio is established with the engagement of the clutches  250 ,  254  and  256 . The clutch  250  connects the input shaft  17  with the sun gear member  222 . The clutch  254  connects the sun gear member  232  with the planet carrier assembly member  246 . The clutch  256  connects the planet carrier assembly member  236  with the ring gear member  244 . The ring gear member  224  rotates at the same speed as the sun gear member  232  and the planet carrier assembly member  246 . The planet carrier assembly member  226  rotates at the same speed as the planet carrier assembly member  236  and the ring gear member  244 . The sun gear member  222  rotates at the same speed as the input shaft  17 . The planet carrier assembly member  226  rotates at a speed determined from the speed of the ring gear member  224 , the speed of the sun gear member  222  and the ring gear/sun gear tooth ratio of the planetary gear set  220 . The ring gear member  234  rotates at the same speed as the output shaft  19 . The ring gear member  234 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  236 , the speed of the sun gear member  232  and the ring gear/sun gear tooth ratio of the planetary gear set  230 . The sun gear member  242  does not rotate. The planet carrier assembly member  246  rotates at a speed determined from the speed of the ring gear member  244  and the ring gear/sun gear tooth ratio of the planetary gear set  240 . The numerical value of the third forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  220 ,  230  and  240 . 
     The fourth forward speed ratio is established with the engagement of the clutches  250 ,  252  and  254 . In this configuration, the input shaft  17  is directly connected with the output shaft  19 . The numerical value of the fourth forward speed ratio is 1. 
     The fifth forward speed ratio is established with the engagement of the clutches  250 ,  252  and  256 . The clutch  250  connects the input shaft  17  with the sun gear member  222 . The clutch  252  connects the input shaft  17  with the planet carrier assembly member  246 . The clutch  256  connects the planet carrier assembly member  236  with the ring gear member  244 . The ring gear member  224  rotates at the same speed as the sun gear member  232 . The planet carrier assembly member  226  rotates at the same speed as the planet carrier assembly member  236  and the ring gear member  244 . The sun gear member  222  and planet carrier assembly member  246  rotate at the same speed as the input shaft  17 . The planet carrier assembly member  226  rotates at a speed determined from the speed of the ring gear member  224 , the speed of the sun gear member  222  and the ring gear/sun gear tooth ratio of the planetary gear set  220 . The ring gear member  234  rotates at the same speed as the output shaft  19 . The ring gear member  234 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  236 , the speed of the sun gear member  232  and the ring gear/sun gear tooth ratio of the planetary gear set  230 . The sun gear member  242  does not rotate. The ring gear member  244  rotates at a speed determined from the speed of the planet carrier assembly member  246  and the ring gear/sun gear tooth ratio of the planetary gear set  240 . The numerical value of the fifth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  220 ,  230  and  240 . 
     The sixth forward speed ratio is established with the engagement of the clutches  252 ,  254  and  256 . The clutch  252  connects the input shaft  17  with the planet carrier assembly member  246 . The clutch  254  connects the sun gear member  232  with the planet carrier assembly member  246 . The clutch  256  connects the planet carrier assembly member  236  with the ring gear member  244 . The ring gear member  224 , sun gear member  232  and planet carrier assembly member  246  rotate at the same speed as the input shaft  17 . The planet carrier assembly member  226  rotates at the same speed as the planet carrier assembly member  236  and the ring gear member  244 . The ring gear member  234  rotates at the same speed as the output shaft  19 . The ring gear member  234 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  236 , the speed of the sun gear member  232  and the ring gear/sun gear tooth ratio of the planetary gear set  230 . The sun gear member  242  does not rotate. The ring gear member  244  rotates at a speed determined from the speed of the planet carrier assembly member  246  and the ring gear/sun gear tooth ratio of the planetary gear set  240 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  230  and  240 . 
     The seventh forward speed ratio is established with the engagement of the clutch  252 ,  256  and the brake  258 . The clutch  252  connects the input shaft  17  with the planet carrier assembly member  246 . The clutch  256  connects the planet carrier assembly member  236  with the ring gear member  244 . The brake  258  connects the sun gear member  232  with the transmission housing  260 . The planet carrier assembly member  226  rotates at the same speed as the planet carrier assembly member  236  and the ring gear member  244 . The ring gear member  224  and sun gear member  232  do not rotate. The ring gear member  234  rotates at the same speed as the output shaft  19 . The ring gear member  234 , and therefore the output shaft  19 , rotates at a speed determined from the speed of the planet carrier assembly member  236  and the ring gear/sun gear tooth ratio of the planetary gear set  230 . The sun gear member  242  does not rotate. The ring gear member  244  rotates at a speed determined from the speed of the planet carrier assembly member  246  and the ring gear/sun gear tooth ratio of the planetary gear set  240 . The numerical value of the seventh forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  230  and  240 . 
     As previously set forth, the truth table of FIG. 3 b  describes the combinations of engagements utilized for the seven forward speed ratios and reverse ratio. The truth table also provides an example of speed ratios that are available with the family member described above. These examples of speed ratios are determined utilizing the tooth ratios given in FIG. 3 b . The R1/S1 value is the tooth ratio of the planetary gear set  220 ; the R2/S2 value is the tooth ratio of the planetary gear set  230 ; and the R3/S3 value is the tooth ratio of the planetary gear set  240 . Also depicted in FIG. 3 b  is a chart representing the ratio steps between adjacent forward speed ratios and the reverse speed ratio. For example, the first to second ratio interchange has a step of 2. It can also be readily determined from the truth table of FIG. 3 b  that all of the single step forward ratio interchanges are of the single transition variety, except for the reverse to first step. 
     A powertrain  310 , shown in FIG. 4 b , includes the engine and torque converter  12 , a planetary transmission  314 , and the final drive mechanism  16 . The planetary transmission  314  includes an input shaft  17  continuously connected with the engine and torque converter  12 , a planetary gear arrangement  318 , and output shaft  19  continuously connected with the final drive mechanism  16 . The planetary gear arrangement  318  includes three planetary gear sets  320 ,  330  and  340 . 
     The planetary gear set  320  includes a sun gear member  322 , a ring gear member  324 , and a planet carrier assembly member  326 . The planet carrier assembly member  326  includes a plurality of pinion gears  327  rotatably mounted on a carrier member  329  and disposed in meshing relationship with both the sun gear member  322  and the ring gear member  324 . 
     The planetary gear set  330  includes a sun gear member  332 , a ring gear member  334 , and a planet carrier assembly member  336 . The planet carrier assembly member  336  includes a plurality of pinion gears  337  rotatably mounted on a carrier member  339  and disposed in meshing relationship with both the sun gear member  332  and the ring gear member  334 . 
     The planetary gear set  340  includes a sun gear member  342 , a ring gear member  344 , and a planet carrier assembly member  346 . The planet carrier assembly member  346  includes a plurality of pinion gears  347  rotatably mounted on a carrier member  349  and disposed in meshing relationship with both the sun gear member  342  and the ring gear member  344 . 
     The planetary gear arrangement  318  also includes six torque-transmitting mechanisms  350 ,  352 ,  354 ,  356 ,  358  and  359 . The torque-transmitting mechanisms  350 ,  352 ,  354  and  356  are of the rotating type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanisms  358  and  359  are stationary type torque-transmitting mechanisms, commonly termed brakes or reaction clutches. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  336 . The sun gear member  342  is continuously connected with the transmission housing  360 . The planet carrier assembly member  326  is continuously connected with the ring gear member  334  through the interconnecting member  370 . The sun gear member  322  is continuously connected with the sun gear member  332  through the interconnecting member  372 . 
     The input shaft  17  is selectively connectable with the sun gear member  322  through the clutch  350 . The input shaft  17  is selectively connectable with the planet carrier assembly member  346  through the clutch  352 . The ring gear member  344  is selectively connectable with the planet carrier assembly member  326  through the clutch  354 . The planet carrier assembly member  346  is selectively connectable with the ring gear member  324  through the clutch  356 . The ring gear member  334  is selectively connectable with the transmission housing  360  through the brake  358 . The ring gear member  324  is selectively connectable with the transmission housing member  360  through the brake  359 . 
     The truth tables given in FIGS. 4 b ,  5   b ,  6   b ,  7   b ,  8   b ,  9   b ,  10   b ,  11   b ,  12   b  and  13   b  show the engagement sequences for the torque-transmitting mechanisms to provide at least seven forward speed ratios and one reverse speed ratio. As shown and described above for the configuration in FIGS. 1 a ,  2   a  and  3   a , those skilled in the art will understand from the respective truth tables how the speed ratios are established through the planetary gear sets identified in the written description. 
     The truth table shown in FIG. 4 b  describes the engagement combination and the engagement sequence necessary to provide the reverse drive ratio and seven forward speed ratios. A sample of the numerical values for the ratios is also provided in the truth table of FIG. 4 b . These values are determined utilizing the ring gear/sun gear tooth ratios also given in FIG. 4 b . The R1/S1 value is the tooth ratio for the planetary gear set  320 ; the R2/S2 value is the tooth ratio for the planetary gear set  330 ; and the R3/S3 value is the tooth ratio for the planetary gear set  340 . Also given in FIG. 4 b  is a chart describing the step ratios between the adjacent forward speed ratios and the reverse to first forward speed ratio. For example, the first to second forward speed ratio step is 2. It can be readily determined from the truth table of FIG. 4 b  that each of the forward single step ratio interchanges is a single transition shift, except for the reverse to first step. The chart also shows that the torque-transmitting mechanisms  354  and  358  can be engaged through the neutral condition to simplify the forward/reverse interchange. 
     Those skilled in the art will recognize that the numerical values of the reverse and second forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  320  and  330 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  330 . The numerical values of the third, sixth and seventh forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  320 ,  330  and  340 . The numerical value of the fourth forward speed ratio is 1. The numerical value of the fifth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  330  and  340 . 
     A powertrain  410 , shown in FIG. 5 a , includes the engine and torque converter  12 , a planetary transmission  414  and the final drive mechanism  16 . The planetary transmission  414  includes a planetary gear arrangement  418 , input shaft  17  and output shaft  19 . The planetary gear arrangement  418  includes three simple planetary gear sets  420 ,  430  and  440 . 
     The planetary gear set  420  includes a sun gear member  422 , a ring gear member  424 , and a planet carrier assembly  426 . The planet carrier assembly  426  includes a plurality of pinion gears  427  rotatably mounted on a carrier member  429  and disposed in meshing relationship with both the sun gear member  422  and the ring gear member  424 . 
     The planetary gear set  430  includes a sun gear member  432 , a ring gear member  434 , and a planet carrier assembly member  436 . The planet carrier assembly member  436  includes a plurality of pinion gears  437  rotatably mounted on a carrier member  439  and disposed in meshing relationship with both the sun gear member  432  and the ring gear member  434 . 
     The planetary gear set  440  includes a sun gear member  442 , a ring gear member  444 , and a planet carrier assembly member  446 . The planet carrier assembly member  446  includes a plurality of pinion gears  447  rotatably mounted on a carrier member  449  and disposed in meshing relationship with both the sun gear member  442  and the ring gear member  444 . 
     The planetary gear arrangement  418  also includes six torque-transmitting mechanisms  450 ,  452 ,  454 ,  456 ,  458  and  459 , each of which is a rotating-type torque-transmitting mechanism, commonly termed clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the ring gear member  434 . The ring gear member  444  is continuously connected with the transmission housing  460 . The planet carrier assembly member  426  is continuously connected with the planet carrier assembly member  436  through the interconnecting member  470 . The ring gear member  424  is continuously connected with the sun gear member  432  through the interconnecting member  472 . 
     The planet carrier assembly member  426  is selectively connectable with the input shaft  17  through the clutch  450 . The sun gear member  442  is selectively connectable with the input shaft  17  through the clutch  452 . The planet carrier assembly member  436  is selectively connectable with the planet carrier assembly member  446  through the clutch  454 . The sun gear member  432  is selectively connectable with the sun gear member  442  through the clutch  456 . The sun gear member  432  is selectively connectable with the planet carrier assembly member  446  through the clutch  458 . The sun gear member  422  is selectively connectable with the sun gear member  442  through the clutch  459 . 
     The truth table shown in FIG. 5 b  describes the engagement combination and sequence of the torque-transmitting mechanisms  450 ,  452 ,  454 ,  456 ,  458  and  459  that are employed to provide the two reverse drive ratios and the eight forward speed ratios. It should be noted that the torque-transmitting mechanisms  452  and  454  are engaged through the neutral condition to simplify the forward/reverse interchange. 
     Also given in the truth table of FIG. 5 b  is a set of numerical values that are attainable with the present invention utilizing the ring gear/sun gear tooth ratios shown. The R1/S1 value is the tooth ratio of the planetary gear set  420 ; the R2/S2 value is the tooth ratio of the planetary gear set  430 ; and the R3/S3 value is the tooth ratio of the planetary gear set  440 . 
     FIG. 5 b  also provides a chart of the ratio steps between adjacent forward ratios and between the reverse (Reverse  1 ) and first forward ratio. For example, the ratio step between the first and second forward ratios is 1.67. Those skilled in the art will recognize that the numerical values of the reverse and sixth forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  430  and  440 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  440 . The numerical values of the second, third, fifth and eighth forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  420 ,  430  and  440 . The numerical value of the fourth forward speed ratio is 1. The numerical value of the seventh forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  430 . 
     A powertrain  510 , shown in FIG. 6 a , includes an engine and torque converter  12 , a planetary gear transmission  514  and the final drive mechanism  16 . The planetary transmission  514  includes the input shaft  17 , a planetary gear arrangement  518  and the output shaft  19 . The planetary gear arrangement  518  includes three planetary gear sets  520 ,  530  and  540 . 
     The planetary gear set  520  includes a sun gear member  522 , a ring gear member  524 , and a planet carrier assembly  526 . The planet carrier assembly  526  includes a plurality of pinion gears  527  rotatably mounted on a carrier member  529  and disposed in meshing relationship with both the sun gear member  522  and the ring gear member  524 . 
     The planetary gear set  530  includes a sun gear member  532 , a ring gear member  534 , and a planet carrier assembly member  536 . The planet carrier assembly member  536  includes a plurality of pinion gears  537  rotatably mounted on a carrier member  539  and disposed in meshing relationship with both the sun gear member  532  and the ring gear member  534 . 
     The planetary gear set  540  includes a sun gear member  542 , a ring gear member  544 , and a planet carrier assembly member  546 . The planet carrier assembly member  546  includes a plurality of pinion gears  547  rotatably mounted on a carrier member  549  and disposed in meshing relationship with both the sun gear member  542  and the ring gear member  544 . 
     The planetary gear arrangement  518  also includes six torque-transmitting mechanisms  550 ,  552 ,  554 ,  556 ,  558  and  559 . The torque-transmitting mechanisms  550 ,  552 ,  554  and  556  are rotating-type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanisms  558  and  559  are stationary-type torque-transmitting mechanisms, commonly termed brakes or reaction clutches. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  536 . The sun gear member  542  is continuously connected with the transmission housing  560 . The planet carrier assembly member  526  is continuously connected with the ring gear member  534  through the interconnecting member  570 . The ring gear member  524  is continuously connected with the planet carrier assembly member  536  through the interconnecting member  572 . 
     The sun gear member  532  is selectively connectable with the input shaft  17  through the clutch  550 . The planet carrier assembly member  546  is selectively connectable with the input shaft  17  through the clutch  552 . The ring gear member  534  is selectively connectable with the ring gear member  544  through the clutch  554 . The sun gear member  522  is selectively connectable with the planet carrier assembly member  546  through the clutch  556 . The planet carrier assembly member  526  is selectively connectable with the transmission housing  560  through the brake  558 . The sun gear member  522  is selectively connectable with the transmission housing  560  through the brake  559 . 
     The truth table shown in FIG. 6 b  describes the engagement sequence and combination of the torque-transmitting mechanisms to provide the reverse speed ratio and seven forward speed ratios. It should be noted that the torque-transmitting mechanisms  550  and  558  can remain engaged through the neutral condition, thereby simplifying the forward/reverse interchange. It can also be determined from the truth table of FIG. 6 b  that all of the single step forward ratio interchanges are of the single transition variety, except for the reverse to first step. The chart of FIG. 6 b  describes the ratio steps between adjacent forward speed ratios and the ratio step between the reverse and first forward speed ratio. 
     Those skilled in the art, upon reviewing the truth table and the schematic representation of FIG. 6 a , can determine that the numerical value of the reverse speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  520 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  530 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  520  and  530 . The numerical value of the third forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  520 ,  530  and  540 . The numerical value of the fourth forward speed ratio is 1. The numerical value of the fifth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  530  and  540 . The numerical values of the sixth and seventh forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  520  and  540 . 
     The sample speed ratios given in the truth table are determined utilizing the tooth ratio values also given in FIG. 6 b . The R1/S1 value is the tooth ratio of the planetary gear set  520 ; the R2/S2 value is the tooth ratio of the planetary gear set  530 ; and the R3/S3 value is the tooth ratio of the planetary gear set  540 . 
     A powertrain  610 , shown in FIG. 7 a , has the engine and torque converter  12 , a planetary transmission  614  and the final drive mechanism  16 . The planetary transmission  614  includes the input shaft  17 , a planetary gear arrangement  618  and the output shaft  19 . The planetary gear arrangement  618  includes three planetary gear sets  620 ,  630  and  640 . 
     The planetary gear set  620  includes a sun gear member  622 , a ring gear member  624 , and a planet carrier assembly  626 . The planet carrier assembly  626  includes a plurality of pinion gears  627  rotatably mounted on a carrier member  629  and disposed in meshing relationship with both the sun gear member  622  and the ring gear member  624 . 
     The planetary gear set  630  includes a sun gear member  632 , a ring gear member  634 , and a planet carrier assembly member  636 . The planet carrier assembly member  636  includes a plurality of pinion gears  637  rotatably mounted on a carrier member  639  and disposed in meshing relationship with both the sun gear member  632  and the ring gear member  634 . 
     The planetary gear set  640  includes a sun gear member  642 , a ring gear member  644 , and a planet carrier assembly member  646 . The planet carrier assembly member  646  includes a plurality of pinion gears  647  rotatably mounted on a carrier member  649  and disposed in meshing relationship with both the sun gear member  642  and the ring gear member  644 . 
     The planetary gear arrangement  618  also includes six torque-transmitting mechanisms  650 ,  652 ,  654 ,  656 ,  658  and  659 . The torque-transmitting mechanisms  650 ,  652 ,  654 ,  656  and  658  are rotating-type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanism  659  is a stationary-type torque-transmitting mechanism, commonly termed brake or reaction clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  626 . The ring gear member  644  is continuously connected with the transmission housing  660 . The ring gear member  624  is continuously connected with the planet carrier assembly member  636  through the interconnecting member  670 . The planet carrier assembly member  626  is continuously connected with the ring gear member  634  through the interconnecting member  672 . 
     The sun gear member  622  is selectively connectable with the input shaft  17  through the clutch  650 . The sun gear member  632  is selectively connectable with the input shaft  17  through the clutch  652 . The planet carrier assembly member  646  is selectively connectable with the input shaft  17  through the clutch  654 . The planet carrier assembly member  636  is selectively connectable with the sun gear member  642  through the clutch  656 . The sun gear member  632  is selectively connectable with the sun gear member  642  through the clutch  658 . The planet carrier assembly member  646  is selectively connectable with the transmission housing  660  through the brake  659 . 
     The truth table shown in FIG. 7 b  describes the combination of torque-transmitting mechanism engagements that will provide the reverse drive ratio and seven forward speed ratios, as well as the sequence of these engagements and interchanges. The torque-transmitting mechanisms  656  and  659  can be engaged through the neutral condition, thereby simplifying the forward/reverse interchange. 
     The ratio values given are by way of example and are established utilizing the ring gear/sun gear tooth ratios given in FIG. 7 b . For example, the R1/S1 value is the tooth ratio of the planetary gear set  620 ; the R2/S2 value is the tooth ratio of the planetary gear set  630 ; and the R3/S3 value is the tooth ratio of the planetary gear set  640 . The ratio steps between adjacent forward ratios and the reverse to first ratio are also given in FIG. 7 b.    
     Those skilled in the art will, upon reviewing the truth table of FIG. 7 b , recognize that the numerical value of the reverse speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  630 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  620 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  620  and  630 . The numerical value of the third forward speed ratio is 1. The numerical value of the fourth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  620 ,  630  and  640 . The numerical value of the fifth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  620  and  640 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  640 . The numerical value of the seventh forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  630  and  640 . 
     A powertrain  710 , shown in FIG. 8 a , has the conventional engine and torque converter  12 , a planetary transmission  714 , and the conventional final drive mechanism  16 . The engine and torque converter  12  are drivingly connected with the planetary transmission  714  through the input shaft  17 . The planetary transmission  714  is drivingly connected with the final drive mechanism  16  through the output shaft  19 . The planetary transmission  714  includes a planetary gear arrangement  718  that has a first planetary gear set  720 , a second planetary gear set  730 , and a third planetary gear set  740 . 
     The planetary gear set  720  includes a sun gear member  722 , a ring gear member  724 , and a planet carrier assembly  726 . The planet carrier assembly  726  includes a plurality of pinion gears  727  rotatably mounted on a carrier member  729  and disposed in meshing relationship with both the sun gear member  722  and the ring gear member  724 . 
     The planetary gear set  730  includes a sun gear member  732 , a ring gear member  734 , and a planet carrier assembly member  736 . The planet carrier assembly member  736  includes a plurality of pinion gears  737  rotatably mounted on a carrier member  739  and disposed in meshing relationship with both the sun gear member  732  and the ring gear member  734 . 
     The planetary gear set  740  includes a sun gear member  742 , a ring gear member  744 , and a planet carrier assembly member  746 . The planet carrier assembly member  746  includes a plurality of pinion gears  747  rotatably mounted on a carrier member  749  and disposed in meshing relationship with both the sun gear member  742  and the ring gear member  744 . 
     The planetary gear arrangement  718  also includes six torque-transmitting mechanisms  750 ,  752 ,  754 ,  756 ,  758  and  759 . The torque-transmitting mechanisms  750 ,  752 ,  754 ,  756  and  758  are rotating-type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanism  759  is a stationary-type torque transmitting mechanism, commonly termed brake or reaction clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  726 . The ring gear member  744  is continuously connected with the transmission housing  760 . The ring gear member  724  is continuously connected with the sun gear member  732  through the interconnecting member  770 . The planet carrier assembly member  726  is continuously connected with the planet carrier assembly member  736  through the interconnecting member  772 . 
     The sun gear member  722  is selectively connectable with the input shaft  17  through the clutch  750 . The ring gear member  734  is selectively connectable with the input shaft  17  through the clutch  752 . The planet carrier assembly member  746  is selectively connectable with the input shaft  17  through the clutch  754 . The sun gear member  732  is selectively connectable with the sun gear member  742  through clutch  756 . The ring gear member  734  is selectively connectable with the sun gear member  742  through the clutch  758 . The planet carrier assembly member  746  is selectively connectable with the transmission housing  760  through the brake  759 . 
     The truth table of FIG. 8 b  defines the torque-transmitting mechanism engagement sequence utilized for each of the forward speed ratios and the reverse speed ratio. Also given in the truth table is a set of numerical values that are attainable with the present invention utilizing the ring gear/sun gear tooth ratios given in FIG. 8 b . The R1/S1 value is the tooth ratio of the planetary gear set  720 ; the R2/S2 value is the tooth ratio of the planetary gear set  730 ; and the R3/S3 value is the tooth ratio of the planetary gear set  740 . 
     FIG. 8 b  also provides a chart of the ratio steps between adjacent forward ratios and between the reverse and first forward ratio. For example, the ratio step between the first and second forward ratios is 1.87. Those skilled in the art will recognize that the numerical value of the reverse speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  720  and  730 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  720 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  730 . The numerical value of the third forward speed ratio is 1. The numerical value of the fourth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  730  and  740 . The numerical value of the fifth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  720  and  740 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  740 . The numerical value of the seventh forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  720 ,  730  and  740 . 
     A powertrain  810 , shown in FIG. 9 a , has the conventional engine and torque converter  12 , a planetary transmission  814 , and the final drive mechanism  16 . The engine and torque converter  12  are drivingly connected with the planetary transmission  814  through the input shaft  17 . The planetary transmission  814  is drivingly connected with the final drive mechanism  16  through the output shaft  19 . The planetary transmission  814  includes a planetary gear arrangement  818  that has a first planetary gear set  820 , a second planetary gear set  830 , and a third planetary gear set  840 . 
     The planetary gear set  820  includes a sun gear member  822 , a ring gear member  824 , and a planet carrier assembly  826 . The planet carrier assembly  826  includes a plurality of pinion gears  827  rotatably mounted on a carrier member  829  and disposed in meshing relationship with both the sun gear member  822  and the ring gear member  824 . 
     The planetary gear set  830  includes a sun gear member  832 , a ring gear member  834 , and a planet carrier assembly member  836 . The planet carrier assembly member  836  includes a plurality of pinion gears  837  rotatably mounted on a carrier member  839  and disposed in meshing relationship with both the sun gear member  832  and the ring gear member  834 . 
     The planetary gear set  840  includes a sun gear member  842 , a ring gear member  844 , and a planet carrier assembly member  846 . The planet carrier assembly member  846  includes a plurality of pinion gears  847  rotatably mounted on a carrier member  849  and disposed in meshing relationship with both the sun gear member  842  and the ring gear member  844 . 
     The planetary gear arrangement  818  also includes six torque-transmitting mechanisms  850 ,  852 ,  854 ,  856 ,  858  and  859 . The torque-transmitting mechanisms  850 ,  852 ,  854 ,  856  and  858  are of the rotating-type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanism  859  is a stationary-type torque-transmitting mechanism, commonly termed brake or reaction clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  826 . The planet carrier assembly member  846  is continuously connected with the transmission housing  860 . The ring gear member  824  is continuously connected with the planet carrier assembly member  836  through the interconnecting member  870 . The planet carrier assembly member  826  is continuously connected with the ring gear member  834  through the interconnecting member  872 . 
     The planet carrier assembly member  836  is selectively connectable with the input shaft  17  through the clutch  850 . The sun gear member  822  is selectively connectable with the input shaft  17  through the clutch  852 . The sun gear member  842  is selectively connectable with the input shaft  17  through the clutch  854 . The sun gear member  832  is selectively connectable with the sun gear member  842  through the clutch  856 . The sun gear member  832  is selectively connectable with the ring gear member  844  through the clutch  858 . The ring gear member  824  is selectively connectable with the transmission housing  860  through the brake  859 . 
     The truth table shown in FIG. 9 b  defines the torque-transmitting mechanism engagement sequence that provides the reverse ratio and seven forward speed ratios shown in the truth table and available with the planetary gear arrangement  818 . The truth table indicates that the torque-transmitting mechanisms  854  and  859  can remain engaged through the neutral condition, thereby simplifying the forward/reverse interchange. A sample of numerical values for the individual ratios is also given in the truth table of FIG. 9 b . These numerical values have been calculated using the ring gear/sun gear tooth ratios also given by way of example in FIG. 9 b . The R1/S1 value is the tooth ratio of the planetary gear set  820 ; the R2/S2 value is the tooth ratio of the planetary gear set  830 ; and the R3/S3 value is the tooth ratio of the planetary gear set  840 . It can be readily recognized from the truth table that all of the single step forward interchanges are single transition ratio interchanges. FIG. 9 b  also describes the ratio steps between adjacent forward ratios and between the reverse and first forward ratio. For example, the ratio step between the first and second forward ratios is 2.02. 
     Those skilled in the art of planetary transmissions will recognize that the numerical values of the reverse and sixth forward speed ratios are determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  830 . The numerical values of the first and seventh forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  830  and  840 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  820 . The numerical value of the third forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  820 ,  830  and  840 . The numerical value of the fourth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  820  and  830 . The numerical value of the fifth forward speed ratio is 1. 
     The powertrain  910 , shown in FIG. 10 a , includes the conventional engine and torque converter  12 , a planetary transmission  914 , and the conventional final drive mechanism  16 . The engine and torque converter  12  are drivingly connected with the planetary transmission  914  through the input shaft  17 . The planetary transmission  914  is drivingly connected with the final drive mechanism  16  through the output shaft  19 . The planetary transmission  914  includes a planetary gear arrangement  918  that has a first planetary gear set  920 , a second planetary gear set  930 , and a third planetary gear set  940 . 
     The planetary gear set  920  includes a sun gear member  922 , a ring gear member  924 , and a planet carrier assembly  926 . The planet carrier assembly  926  includes a plurality of pinion gears  927  that are rotatably mounted on a carrier member  929  and disposed in meshing relationship with the sun gear member  922  and the ring gear member  924 , respectively. 
     The planetary gear set  930  includes a sun gear member  932 , a ring gear member  934 , and a planet carrier assembly member  936 . The planet carrier assembly member  936  includes a plurality of pinion gears  937  rotatably mounted on a carrier member  939  and disposed in meshing relationship with both the sun gear member  932  and the ring gear member  934 . 
     The planetary gear set  940  includes a sun gear member  942 , a ring gear member  944 , and a planet carrier assembly member  946 . The planet carrier assembly member  946  includes a plurality of pinion gears  947  rotatably mounted on a carrier member  949  and disposed in meshing relationship with both the sun gear member  942  and the ring gear member  944 . 
     The planetary gear arrangement  918  also includes six torque-transmitting mechanisms  950 ,  952 ,  954 ,  956 ,  958  and  959 . The torque-transmitting mechanisms  950 ,  952 ,  954 ,  956  and  958  are of the rotating-type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanism  959  is a stationary-type torque-transmitting mechanism, commonly termed brake or reaction clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  936 . The ring gear member  944  is continuously connected with the transmission housing  960 . The planet carrier assembly member  926  is continuously connected with the ring gear member  934  through the interconnecting member  970 . The sun gear member  922  is continuously connected with the sun gear member  932  through the interconnecting member  972 . 
     The planet carrier assembly member  926  is selectively connectable with the input shaft  17  through the clutch  950 . The ring gear member  924  is selectively connectable with the input shaft  17  through the clutch  952 . The planet carrier assembly member  946  is selectively connectable with the input shaft  17  through the clutch  954 . The sun gear member  932  is selectively connectable with the sun gear member  942  through the clutch  956 . The planet carrier assembly member  926  is selectively connectable with the sun gear member  942  through the clutch  958 . The planet carrier assembly member  946  is selectively connectable with the transmission housing  960  through the brake  959 . 
     The truth table of FIG. 10 b  describes the torque-transmitting mechanism engagement sequence utilized to provide the reverse speed ratio and seven forward speed ratios. The truth table also provides a set of examples for the ratios for each of the reverse and forward speed ratios. These numerical values have been determined utilizing the ring gear/sun gear tooth ratios given in FIG. 10 b . The R1/S1 value is the tooth ratio of the planetary gear set  920 ; the R2/S2 value is the tooth ratio of the planetary gear set  930 ; and the R3/S3 value is the tooth ratio of the planetary gear set  940 . 
     Those skilled in the art, upon reviewing the engagement combinations, will recognize that the numerical values of the reverse and first forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  920  and  930 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  930 . The numerical value of the third forward speed ratio is 1. The numerical value of the fourth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  930  and  940 . The numerical values of the fifth and seventh forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  920 ,  930  and  940 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  940 . 
     A powertrain  1010 , shown in FIG. 11 a , includes the conventional engine and torque converter  12 , a planetary transmission  1014 , and the conventional final drive mechanism  16 . The engine and torque converter are drivingly connected with the planetary transmission  1014  through the input shaft  17 . The planetary transmission  1014  is drivingly connected with the final drive mechanism  16  through the output shaft  19 . The planetary transmission  1014  includes a planetary gear arrangement  1018  that has a first planetary gear set  1020 , a second planetary gear set  1030 , and a third planetary gear set  1040 . 
     The planetary gear set  1020  includes a sun gear member  1022 , a ring gear member  1024 , and a planet carrier assembly  1026 . The planet carrier assembly  1026  includes a plurality of pinion gears  1027  rotatably mounted on a carrier member  1029  and disposed in meshing relationship with both the sun gear member  1022  and the ring gear member  1024 . 
     The planetary gear set  1030  includes a sun gear member  1032 , a ring gear member  1034 , and a planet carrier assembly member  1036 . The planet carrier assembly member  1036  includes a plurality of pinion gears  1037  rotatably mounted on a carrier member  1039  and disposed in meshing relationship with both the sun gear member  1032  and the ring gear member  1034 . 
     The planetary gear set  1040  includes a sun gear member  1042 , a ring gear member  1044 , and a planet carrier assembly member  1046 . The planet carrier assembly member  1046  includes a plurality of pinion gears  1047  rotatably mounted on a carrier member  1049  and disposed in meshing relationship with both the sun gear member  1042  and the ring gear member  1044 . 
     The planetary gear arrangement  1018  also includes six torque-transmitting mechanisms  1050 ,  1052 ,  1054 ,  1056 ,  1058  and  1059 , each of which is a rotating-type torque-transmitting mechanism, commonly termed clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  1036 . The ring gear member  1044  is continuously connected with the transmission housing  1060 . The planet carrier assembly member  1026  is continuously connected with the ring gear member  1034  through the interconnecting member  1070 . The sun gear member  1022  is continuously connected with the sun gear member  1032  through the interconnecting member  1072 . 
     The planet carrier assembly member  1026  is selectively connectable with the input shaft  17  through the clutch  1050 . The ring gear member  1024  is selectively connectable with the input shaft  17  through the clutch  1052 . The planet carrier assembly member  1046  is selectively connectable with the input shaft  17  through the clutch  1054 . The sun gear member  1032  is selectively connectable with the sun gear member  1042  through the clutch  1056 . The planet carrier assembly member  1026  is selectively connectable with the sun gear member  1042  through the clutch  1058 . The planet carrier assembly member  1046  is selectively connectable with the sun gear member  1042  through the clutch  1059 . 
     The truth table shown in FIG. 11 b  describes the engagement combinations and the engagement sequence necessary to provide the reverse drive ratio and the seven forward speed ratios. A sample of the numerical values for the ratios is also provided in the truth table of FIG. 11 b . These values are determined utilizing the ring gear/sun gear tooth ratios also given in FIG. 11 b . The R1/S1 value is the tooth ratio for the planetary gear set  1020 ; the R2/S2 value is the tooth ratio for the planetary gear set  1030 ; and the R3/S3 value is the tooth ratio for the planetary gear set  1040 . Also given in FIG. 11 b  is a chart describing the step ratios between the adjacent forward speed ratios and the reverse to first forward speed ratio. 
     Those skilled in the art will recognize that the numerical values of the reverse and first forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1020  and  1030 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  1030 . The numerical value of the third forward speed ratio is 1. The numerical value of the fourth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1030  and  1040 . The numerical values of the fifth and seventh forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1020 ,  1030  and  1040 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  1040 . 
     A powertrain  1110 , shown in FIG. 12 a , has a conventional engine and torque converter  12 , a planetary transmission  1114 , and the conventional final drive mechanism  16 . The planetary transmission  1114  includes a planetary gear arrangement  1118  which is connected with the engine and torque converter  12  through the input shaft  17  and with the final drive mechanism  16  through the output shaft  19 . The planetary gear arrangement  1118  includes three planetary gear sets  1120 ,  1130  and  1140 . 
     The planetary gear set  1120  includes a sun gear member  1122 , a ring gear member  1124 , and a planet carrier assembly  1126 . The planet carrier assembly  1126  includes a plurality of pinion gears  1127  rotatably mounted on a carrier member  1129  and disposed in meshing relationship with both the sun gear member  1122  and the ring gear member  1124 . 
     The planetary gear set  1130  includes a sun gear member  1132 , a ring gear member  1134 , and a planet carrier assembly member  1136 . The planet carrier assembly member  1136  includes a plurality of intermeshing pinion gears  1137  that are rotatably mounted on a carrier member  1139  and disposed in meshing relationship with both the sun gear member  1132  and the ring gear member  1134 . 
     The planetary gear set  1140  includes a sun gear member  1142 , a ring gear member  1144 , and a planet carrier assembly member  1146 . The planet carrier assembly member  1146  includes a plurality of pinion gears  1147  rotatably mounted on a carrier member  1149  and disposed in meshing relationship with both the sun gear member  1142  and the ring gear member  1144 . 
     The planetary gear arrangement  1118  also includes six torque-transmitting mechanisms  1150 ,  1152 ,  1154 ,  1156 ,  1158  and  1159 , each of which is a rotating-type torque-transmitting mechanism, commonly termed clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  1126 . The ring gear member  1144  is continuously connected with the transmission housing  1160 . The ring gear member  1124  is continuously connected with the planet carrier assembly member  1136  through the interconnecting member  1170 . The planet carrier assembly member  1126  is continuously connected with the ring gear member  1134  through the interconnecting member  1172 . 
     The sun gear member  1122  is selectively connectable with the input shaft  17  through the clutch  1150 . The sun gear member  1132  is selectively connectable with the input shaft  17  through the clutch  1152 . The planet carrier assembly member  1146  is selectively connectable with the input shaft  17  through the clutch  1154 . The planet carrier assembly member  1136  is selectively connectable with the sun gear member  1142  through the clutch  1156 . The sun gear member  1132  is selectively connectable with the sun gear member  1142  through the clutch  1158 . The planet carrier assembly member  1146  is selectively connectable with the sun gear member  1142  through the clutch  1159 . 
     The truth table shown in FIG. 12 b  describes the engagement sequence and engagement combinations utilized with the present family member to provide a reverse drive ratio and seven forward speed ratios. The truth table of FIG. 12 b  also provides a set of example numbers that can be established in the planetary gear arrangement  1118  utilizing the ring gear/sun gear tooth ratios. The R1/S1 value is the ring gear/sun gear tooth ratio of the planetary gear set  1120 ; the R2/S2 value is the ring gear/sun gear tooth ratio of the planetary gear set  1130 ; and the R3/S3 value is the ring gear/sun gear tooth ratio of the planetary gear set  1140 . 
     The chart of FIG. 12 b  describes the ratio steps between adjacent forward speed ratios for a seven-speed transmission. These step ratios are established utilizing the example speed ratios given in the truth table. As also shown in the truth table, the torque-transmitting mechanisms  1156  and  1159  can remain engaged through the neutral condition, thereby simplifying the forward/reverse interchange. 
     Those skilled in the art will recognize that the numerical value of the reverse speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  1130 . The numerical value of the first forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  1120 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1120  and  1130 . The numerical value of the third forward speed ratio is 1. The numerical value of the fourth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1120 ,  1130  and  1140 . The numerical value of the fifth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1120  and  1140 . The numerical value of the sixth forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  1140 . The numerical value of the seventh forward speed ratio is determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1130  and  1140 . 
     A powertrain  1210 , shown in FIG. 13 a , includes the conventional engine and torque converter  12 , a planetary transmission  1214 , and the conventional final drive mechanism  16 . The engine and torque converter are drivingly connected with the planetary transmission  1214  through the input shaft  17 . The planetary transmission  1214  is drivingly connected with the final drive mechanism  16  through the output shaft  19 . The planetary transmission  1214  includes a planetary gear arrangement  1218  that has a first planetary gear set  1220 , a second planetary gear set  1230 , and a third planetary gear set  1240 . 
     The planetary gear set  1220  includes a sun gear member  1222 , a ring gear member  1224 , and a planet carrier assembly  1226 . The planet carrier assembly  1226  includes a plurality of pinion gears  1227  rotatably mounted on a carrier member  1229  and disposed in meshing relationship with both the sun gear member  1222  and the ring gear member  1224 . 
     The planetary gear set  1230  includes a sun gear member  1232 , a ring gear member  1234 , and a planet carrier assembly member  1236 . The planet carrier assembly member  1236  includes a plurality of pinion gears  1237  rotatably mounted on a carrier member  1239  and disposed in meshing relationship with both the sun gear member  1232  and the ring gear member  1234 . 
     The planetary gear set  1240  includes a sun gear member  1242 , a ring gear member  1244 , and a planet carrier assembly member  1246 . The planet carrier assembly member  1246  includes a plurality of pinion gears  1247  and  1248  rotatably mounted on a carrier member  1249  and disposed in meshing relationship with both the sun gear member  1242  and the ring gear member  1244 . 
     The planetary gear arrangement  1218  also includes six torque transmitting mechanisms  1250 ,  1252 ,  1254 ,  1256 ,  1258  and  1259 . The torque-transmitting mechanisms  1250 ,  1252 ,  1254 ,  1256  and  1258  are rotating-type torque-transmitting mechanisms, commonly termed clutches. The torque-transmitting mechanism  1259  is a stationary-type torque-transmitting mechanism, commonly termed brake or reaction clutch. 
     The input shaft  17  is not continuously connected with any planetary gear member. The output shaft  19  is continuously connected with the planet carrier assembly member  1236 . The ring gear member  1244  is continuously connected with the transmission housing  1260 . The ring gear member  1234  is continuously connected with the planet carrier assembly member  1226  through the interconnecting member  1270 . The sun gear member  1232  is continuously connected with the ring gear member  1224  through the interconnecting member  1272 . 
     The planet carrier assembly member  1226  is selectively connectable with the input shaft  17  through the clutch  1250 . The ring gear member  1224  is selectively connectable with the input shaft  17  through the clutch  1252 . The planet carrier assembly member  1246  is selectively connectable with the input shaft  17  through the clutch  1254 . The sun gear member  1222  is selectively connectable with the planet carrier assembly member  1246  through the clutch  1256 . The sun gear member  1222  is selectively connectable with the sun gear member  1242  through the clutch  1258 . The ring gear member  1234  is selectively connectable with the transmission housing  1260  through the brake  1259 . 
     The truth table shown in FIG. 13 b  describes the engagement combinations and the engagement sequence necessary to provide the reverse drive ratio and seven forward speed ratios. A sample of the numerical values for the ratios is also provided in the truth table of FIG. 13 b . These values are determined utilizing the ring gear/sun gear tooth ratios also given in FIG. 13 b . The R1/S1 value is the tooth ratio for the planetary gear set  1220 ; the R2/S2 value is the tooth ratio for the planetary gear set  1230 ; and the R3/S3 value is the tooth ratio for the planetary gear set  1240 . Also given in FIG. 13 b  is a chart describing the step ratios between the adjacent forward speed ratios and the reverse to first forward speed ratio. 
     Those skilled in the art will recognize that the numerical values of the reverse, fourth and sixth forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1220  and  1230 . The numerical values of the first, third and seventh forward speed ratios are determined utilizing the ring gear/sun gear tooth ratios of the planetary gear sets  1220 ,  1230  and  1240 . The numerical value of the second forward speed ratio is determined utilizing the ring gear/sun gear tooth ratio of the planetary gear set  1220 . The numerical value of the fifth forward speed ratio is 1. 
     While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.