Abstract:
An embodiment provides a method shifting a multispeed transmission. The multispeed transmission includes multiple gear paths having alternating speed ratios and a plurality of shift members. Each shift member is selectively moveable to engage a speed ratio of the transmission. The method includes directing a shift finger to contact a first shift member, moving the first shift member generally in a first generally orthogonal direction to engage a first gear, and moving the shift finger in a second generally orthogonal direction to an intermediate configuration. The shift finger will not contact a selector rail when moved in the first direction when the shift finger is in the intermediate configuration. The method also includes moving the shift finger generally in the second generally orthogonal direction to a second engaged configuration. The shift finger will contact a second shift member when moved in the first direction when the shift finger is in the second engaged configuration.

Description:
TECHNICAL FIELD 
     The technical field is shifting mechanisms for dual clutch transmissions. 
     BACKGROUND 
     Twin-clutch, twin-shaft, dual shaft, or dual clutch transmissions of the alternating shifting type are well known in the prior art. Various types of twin clutch transmissions have been proposed and put into practical use, particularly in the field of wheeled motor vehicles. Traditional twin clutch transmissions are of a type in which gears are parted into two groups, each group having an individual main clutch, so that the operative condition of each group of gears is carried out by selectively engaging a corresponding main clutch. Twin clutch transmissions are used in vehicles to improve the transition from one gear ratio to another and, in doing so, improve the efficiency of the transmission. The gears of each group are typically individually engaged so as to rotatably connect a transmission input shaft to a transmission output shaft for transmitting torque at differing ratios. The differing ratios may be engaged by multiple shift clutches. A typical dual clutch is illustrated in commonly owned U.S. Pat. No. 7,082,850, to Hughes, the disclosure of which is hereby incorporated by reference in its entirety. 
     In such transmissions, the main section may be shifted by means of a shift control system. Typical shift control systems include multiple actuators for engaging and disengaging the multiple shift clutches. The actuators may be pneumatic, electric, or hydraulic, and typically, one double acting actuator controls each shift clutch. The shift control system may also include a control logic for controlling the engagement of the main clutches, and the shift clutches to provide a desired gear ratio during vehicle operation. Generally, one ratio for each group may be simultaneously engaged with only one main clutch engaged during vehicle operation. To complete a shift in a dual clutch transmission, the engaged main clutch is disengaged as the disengaged main clutch is engaged. Accordingly, the disengaged group may be reconfigured as the engaged shift clutch is disengaged while another shift clutch of the group is engaged to provide a higher or low gear ratio to complete the next main clutch disengage/engage process. 
     Typical non-dual clutch transmissions may be shifted by a single actuator acting as a X-Y shift control device. A X-Y shift control device may be operated by a manual lever or by a pneumatic, hydraulic, or electrical control. Prior X-Y shift control devices are disclosed in U.S. Pat. Nos. 4,873,881 and 5,281,902, to Edelen, U.S. Pat. No. 4,899,607 to Stainton, and U.S. Pat. No. 6,227,067 to Steeby, which are assigned to the assignee of the present application, the disclosures of which is hereby incorporated by reference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings, illustrative embodiments are shown in detail. Although the drawings represent some embodiments, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present invention. Further, the embodiments set forth herein are exemplary and are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. 
         FIG. 1  is a schematic illustration, not to scale, of a powertrain system according to an embodiment. 
         FIG. 2  is a schematic illustration of a transmission and dual clutch arrangement according to an embodiment 
         FIG. 3  is a schematic perspective illustration of a portion of a shift control device of the main section of the transmission of  FIG. 1 . 
         FIG. 4  is a perspective illustration of a portion of a shift control device of the main section of the transmission of  FIG. 1 . 
         FIG. 5  is a view taken along line  5 - 5  of  FIG. 4 . 
         FIGS. 6-16  are views similar to  FIG. 5 , with the shift members and shift finger in differing configurations. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a powertrain system  20  is shown in accordance with an embodiment of the present invention. In the illustrated embodiment, powertrain system  20  includes a prime mover  22 , such as a spark-ignited or compression-ignited internal combustion engine, and a transmission  24 . A shift control system  26  operates to engage and disengage gear ratios within the transmission  24 , as discussed in greater detail below. A main clutch assembly  28  is positioned between the prime mover  22  and transmission  24  to selectively engage/disengage the prime mover  22  from transmission  24 . 
     In an embodiment, powertrain system  20  also includes an electronic control unit (ECU)  30  for controlling operation of the prime mover  22 , main clutch assembly  28 , and transmission  24 . In an implementation of the invention, ECU  30  may include a programmable digital computer that is configured to receive various input signals, including without limitation, the operating speed of the prime mover  22 , transmission input speed, selected transmission ratio, transmission output speed and vehicle speed, and processes these signals accordingly to logic rules to control operation of powertrain system  20 . For example, ECU  30  may be programmed to deliver fuel to the prime mover  22  when the prime mover  22  functions as an internal combustion engine. To support this control, each of the prime mover  22 , and main clutch assembly  28  may include its own control system (not shown) contained within ECU  30 . However, it will be appreciated that the present invention is not limited to any particular type or configuration of ECU  30 , or to any specific control logic for governing operation of powertrain system  20 . 
     In the embodiment shown in  FIG. 1 , a transmission output rotation from an output shaft, or output member,  32  is distributed to wheels  34  through a drive shaft  36  and a differential  38 . 
     Referring to  FIG. 2 , an embodiment of a transmission and clutch arrangement for use in the powertrain system  20  is shown. In the illustrated embodiment, transmission  24  includes a first input shaft  40 , a second input shaft  42 , a countershaft  44  that extends substantially parallel with first and second input shafts  40  and  42 , and a plurality of gears which are arranged on and/or around shafts  40 ,  42  and  44 . Although shafts  40 ,  42  and  44  are illustrated as being mounted in a common plane in  FIG. 2 , these shafts may be arranged in different planes. 
     In the embodiment shown in  FIG. 2 , first input shaft  40  is connectable to an output member  46  of the prime mover  22 , such as a flywheel, through a first input gear  46 A and a first main clutch C 1  that is used to establish speed gearing for selected ratios, while second input shaft  42  is connectable to output member  46  through a second input gear  46 B and a second main clutch C 2  that is used for establishing speed gearing for selected ratios, as discussed in greater detail below. In an embodiment of the invention, first and second main clutches C 1  and C 2  are of a normally ON type, which assumes the ON (viz., engaged) state due to a biasing force of a spring and the like under a normal condition and establishes the OFF (viz., disengaged) state due to work of a hydraulic or electric actuator upon receiving a given instruction. Engagement and disengagement of first and second main clutches C 1 , C 2  may function automatically under the control of ECU  30 , and without intervention of a vehicle driver, when powertrain systems operates like an “automatic” transmission. 
     To first input shaft  40  there are connected a first speed input gear  48 , a third speed input gear  50  and a fifth speed input gear  52 , such that gears  48 ,  50 ,  52  rotate together with first input shaft  40 . Similarly, to second input shaft  42  there are connected a sixth speed input gear  54 , a reverse input gear  56 , a second speed input gear  58  and a fourth speed input gear  60 , such that gears  54 ,  56 ,  58  and  60  rotate together with second input shaft  42 . The number of input gears provided on first and second input shafts  40 ,  42  is not limited to the number shown in  FIG. 2 , and may include more or less input gears depending on the number of ratios desired in the transmission. The term “gear,” as stated herein, is used to define the toothed wheels schematically illustrated in  FIG. 2 , as well as manufacturing the toothed features of the wheels directly into first and second input shafts  40 ,  42  and countershaft  44 . 
     To countershaft  44  there are rotatably connected a first speed output gear  62 , a third speed output gear  64 , a fifth speed output gear  66 , a reverse output gear  68 , a second speed output gear  70 , a fourth speed output gear  72 , and a sixth speed output gear  74 . Thus, output gears  62 - 74  rotate around countershaft  44 . Like input gears  48 - 60 , the number of output gears provided on countershaft  44  is not limited to the number shown in  FIG. 2 . 
     Referring still to  FIG. 2 , first speed output gear  62 , third speed output gear  64  and fifth speed output gear  66  are meshed with first speed input gear  48 , third speed input gear  50  and fifth speed input gear  52 , respectively. Similarly, reverse output gear  68 , second speed output gear  70 , and fourth speed output gear  72  and sixth speed output gear  74  are meshed with reverse input gear  56  (through an idler  76 ), second speed input gear  58 , fourth speed input gear  60  and sixth speed input gear  54 , respectively. In another embodiment, transmission  24  may include a second countershaft (not shown) that includes one or more of the output gears rotatably disposed on countershaft  44 . 
     In the embodiment illustrated, the transmission  24  includes a range section  78 , as discussed in greater detail below, although the countershaft  44  may be directly connected for supplying torque to the output member  32 . The transmission  24  also includes axially moveable shift clutches, such as synchronized single or double acting dog-type clutches, which are splined to countershaft  44  for rotation therewith. Specifically, in the embodiment illustrated, the transmission includes a first shift clutch  82 , a second shift clutch  84 , a third shift clutch  86 , and a fourth shift clutch  88 . In the embodiment described herein, the shift clutches  82 ,  84 ,  86  and  88  are controlled by the ECU  30  acting through the shift control system  26 . 
     When the transmission is in a first speed ratio configuration, the first main clutch C 1  is engaged such that torque is transmitted from the first prime mover  22  to the first input shaft  40 , the second main clutch C 2  is disengaged such that generally no torque is transmitted from the first prime mover  22  to the second input shaft  42 , and the shift clutch  84  is engaged with the first speed output gear  62  such torque is transmitted from the first input shaft  40  to the countershaft  44 . 
     When the transmission is in a second speed ratio configuration, the first main clutch C 1  is disengaged such that generally no torque is transmitted from the first prime mover  22  to the first input shaft  40 , the second main clutch C 2  is engaged such that torque is transmitted from the first prime mover  22  to the second input shaft  42 , and the shift clutch  88  is engaged with the gear  70  such torque is transmitted from the second input shaft  42  to the countershaft  44 . 
     When the transmission is in a third speed ratio configuration, the first main clutch C 1  is engaged such that torque is transmitted from the first prime mover  22  to the first input shaft  40 , the second main clutch C 2  is disengaged such that generally no torque is transmitted from the first prime mover  22  to the second input shaft  42 , and the shift clutch  86  is engaged with the gear  64  such torque is transmitted from the first input shaft  40  to the countershaft  44 . 
     Configuring the transmission  24  into a fourth speed ratio configuration, a fifth speed ratio configuration, a sixth speed ratio configuration, and a reverse speed configuration is accomplished in similar fashion. The transmission  24  may be in a neutral configuration when either 1) the first main clutch C 1  and the second main clutch C 2  are disengaged, and/or 2) the shift clutches  82 ,  84 ,  86 ,  88  are disengaged. The shift control system  26  is in a neutral configuration when the shift clutches  82 ,  84 ,  86 ,  88  are disengaged. 
       FIG. 3  illustrates the shift control system  26  to include an X-Y actuator  90  and a shift rail mechanism  92 . Typical X-Y actuators are disclosed in U.S. Pat. Nos. 4,821,590, 4,873,881 5,281,902, and 6,227,067, the disclosures of which are hereby incorporated by reference. In the embodiment illustrated, the actuator  90  includes a shift shaft  94  generally defined by an axis A-A and a shift finger  96  having a shift finger engaging portion  98 . The shift finger  96  extends from the shift shaft  94  to contact a plurality of shift members, commonly referred to as shift blocks or shift gates, as discussed below. 
       FIG. 3  also illustrates a portion of the transmission  24  that is moveable by the shift control system  26  to include a first shift fork  100 , a second shift fork  102 , a third shift fork  104 , a fourth shift fork  106 , a first shift shaft  110 , a second shift shaft  112 , a third shift shaft  114 , a fourth shift shaft  116 , a first shift member  120 , a second shift member  122 , a third shift member  124 , and a fourth shift member  126 . The first shift fork  100  is connected to the first shift shaft  110 , which is connected to the first shift member  120 . The second shift fork  102  is connected to the second shift shaft  112 , which is connected to the second shift member  122 . The third shift fork  104  is connected to the third shift shaft  114 , which is connected to the third shift member  124 . The fourth shift fork  106  is connected to the fourth shift shaft  116 , which is connected to the fourth shift member  126 . 
     Referring back to  FIG. 2 , the first shift clutch  82  is moveable by the first shift fork  100  in an axial direction toward main clutch assembly  28  to fix countershaft  44  for rotation with reverse output gear  68 . Similarly, the second shift clutch  84  is moveable by the second shift fork  102  and may be moved in opposite axial directions to rotationally fix the fourth speed output gear  72  or the first speed output gear  62  to countershaft  44 . The third shift clutch  86  is moveable by the third shift fork  104  and may be selectively moved in opposite axial directions to rotationally fix the third speed output gear  64  or the sixth speed output gear  74  to countershaft  44 . The fourth shift clutch  88  is moveable by the fourth shift fork  108  and may be selectively moved in opposite axial directions to rotationally fix the fifth speed output gear  66  or the second speed output gear  70  to countershaft  44 . In another embodiment of the invention, clutches  82 ,  84 ,  86  and  88  may also be provided on first and second input shafts  40 ,  42  to engage and disengage gears rotatably supported on input shafts  40 ,  42  in a manner substantially similar to the manner in which the gears are engaged on countershaft  44 . 
     The ECU  30  delivers commands to the components of powertrain system  20  based on the receipt and evaluation of various input signals. These commands may include gear ratio interchange commands to the shift control system  26  that indirectly moves clutches  82 ,  84 ,  86 ,  88  to establish the gear ratios between first and second input shafts  40 ,  42  and countershaft  44 . 
     The ECU  30  controls the axial position of each of clutches  82 ,  84 ,  86 ,  88 , through a rail-type X-Y shift control mechanism, as discussed in greater detail below. 
     Operation of transmission  24  will now be described with reference to  FIG. 2 . In a first mode of operation employed during vehicle launch and acceleration, first and second main clutches C 1  and C 2  are initially disengaged and clutch  84  is moved leftward from the neutral position shown in  FIG. 2 , so that first speed output gear  62  is fixed to countershaft  44  by clutch  84 . Upon this movement, power from the prime mover  22  may be transmitted to countershaft  44  by engaging first main clutch C 1 . The power applied to first input shaft  40  is transmitted through first speed input gear  48  to first speed output gear  62  to clutch  84  to countershaft  44  so that a first speed ratio is established in transmission  24 . 
     As the vehicle accelerates and the second speed ratio is desired, clutch  88  is moved rightward from the neutral position shown in  FIG. 2 , so that second speed output gear  70  is fixed to countershaft  44  by clutch  88 . The engagement of clutch  88  occurs while the second main clutch C 2  is disengaged and therefore, power is not transmitted from the prime mover  22  to second input shaft  42 . To engage the second speed ratio, the currently engaged first main clutch C 1  is disengaged while simultaneously or nearly simultaneously engaging the second main clutch C 2 . The resulting power applied to second input shaft  42  is transmitted through second speed input gear  58  to countershaft  44  through second speed output gear  70  and clutch  88 , so that the second speed ratio is established in transmission  24 . This process is repeated in the same manner for up-shifting through the remaining gear ratios, and in a reverse manner for down-shifting from one gear ratio to another. 
     To achieve the reverse gear in transmission  24 , first and second main clutches C 1  and C 2  are disengaged and clutch  82  is moved leftward from the neutral position shown in  FIG. 2 , so that reverse output gear  68  is fixed to countershaft  44  by clutch  82 . The power applied to first input shaft  40  is transmitted from reverse input gear  56  to countershaft  44  through an idler gear  76  and reverse output gear  68 . 
     Under a normal operating state, wherein transmission  24  is configured into a certain speed gearing, both the first main clutch C 1  and the second main clutch C 2  may be kept in their engaged conditions while one of clutches  82 ,  84 ,  86 , and  88  is retained in a power transmitting position. For example, when transmission  24  assumes the fifth speed ratio, both first and second main clutches C 1  and C 2  may be engaged while clutch  88  is engaged with fifth speed output gear  66  and clutches  82 ,  84 , and  86  are in their neutral position shown in  FIG. 2 . Although the first main clutch C 1  and the second main clutch C 2  are engaged, no power is transmitted through the unselected output gears  62 ,  64 ,  68 ,  70 ,  72 , and  74  because these output gears are free to rotate relative to the countershaft  44  when not engaged by a corresponding clutch  82 ,  84 , or  86 . 
     As mentioned above, the illustrated embodiment of the transmission  24  includes the auxiliary transmission range section  78 , as best seen in  FIG. 2 , although the methods and devices described herein may be used without a range section, or with a single clutch transmission. The range section  78  includes a synchronized two-position auxiliary section jaw clutch assembly  150 , a range shaft  152 , a first range shaft gear  154 , a second range shaft gear  156 , a first range gear  160 , and a second range gear  162 . The jaw clutch assembly  150  is axially positioned by means of a range shift fork (not shown), and rotatably fixed to countershaft  44  for rotation therewith. A range section shifting actuator assembly (not shown) is provided for engaging either countershaft  44  with output shaft  32  for direct or high range operation, or engaging countershaft  44  with gear  162  for low range operation of the transmission  24 . 
     Briefly, and with reference to  FIGS. 3-16 , movement of the shift finger engaging portion  98  displaces a selected one of the forks and thereby engages a target gear. Specifically, ECU  30  controls the position of shift finger  96  as the shift finger  96  moves generally in a first generally orthogonal direction FD and generally in a second generally orthogonal direction SD. Generally, the first generally orthogonal direction FD is perpendicular to the second generally orthogonal direction SD, although either the first generally orthogonal direction FD and/or the second generally orthogonal direction SD may be slightly curved as the shift finger rotates generally about a portion of the shift control system  26 , such as the axis A-A of the shift shaft  94 . In the embodiment illustrated, the shift finger  96  moves in the first generally orthogonal direction FD as the shift shaft  94  rotates about the axis A-A. Additionally, the shift finger  96  moves in the second generally orthogonal direction SD as the shift shaft  94  translates along the axis A-A. Accordingly, the shift control system  26  includes a mechanism, such as the actuator  90 , for rotating and translating the shift shaft  94 . Alternatively, the shift finger may be manipulated by a shift control device that does not rotate a shaft, but translates the shift finger. 
     In the embodiment illustrated, the shift finger engaging portion  98  further includes a finger distal shift surface  180 , a finger proximal shift surface  182 , a finger first side surface  184 , and a finger second side surface  186 . 
     As best illustrated in  FIG. 4 , the first shift member  120 , second shift member  122 , third shift member  124 , and fourth shift member  126  each include opposing shift member engaging surfaces. Specifically, the first shift member  120  is defined by a first shift member distal surface  200 , a first shift member proximal surface  202 , a first shift member first side surface  204 , and a first shift member second side surface  206 . 
     The second shift member  122  is defined by a second shift member distal surface  210 , a second shift member proximal surface  212 , a second shift member first side surface  214 , and a second shift member second side surface  216 . The third shift member  124  is defined by a third shift member distal surface  220 , a third shift member proximal surface  222 , a third shift member first side surface  224 , and a third shift member second side surface  226 . Additionally, the fourth shift member  126  is defined by a fourth shift member distal surface  230 , a fourth shift member proximal surface  232 , a fourth shift member first side surface  234 , and a fourth shift member second side surface  236 . 
     The shift finger engaging portion is limited for movement in the second generally orthogonal direction SD between a first lateral extent ( FIG. 16 ) and a second lateral extent ( FIGS. 14 and 15 ). The first shift member  120 , the second shift member  122 , the third shift member  124 , and the fourth shift member  126  may be selectively aligned (as best seen in  FIG. 6 ) such that the shift finger engaging portion  98  may move in the second generally orthogonal direction SD from the first lateral extent to the second lateral extent without moving the shift finger engaging portion  98  in the first lateral direction. Additionally, the shift finger engaging portion  98  may not be moved solely in the second generally orthogonal direction SD between the first lateral extent and the second lateral extent when the transmission is in an engaged speed ratio ( FIGS. 3-5  and  8 - 15 ). 
       FIGS. 4 and 5  illustrate a portion of the shift control system  26  where both the third shift member and the fourth shift member are moved such that the shift clutch  86  is engaged with the gear  64  and the shift clutch  88  is engaged with the gear  70 . In the configuration illustrated in  FIGS. 4 and 5 , the transmission  24  is in the second speed ratio configuration if the second main clutch C 2  is engaged with the first main clutch C 1  disengaged, and the transmission  24  is in the third speed ratio configuration if the first main clutch C 1  is engaged with the second main clutch C 2  disengaged. 
     As best seen in  FIG. 5 , the width of the shift finger engaging portion  98  in the generally orthogonal direction SD (between surfaces  184  and  186 ) is less than the width between adjacent shift members (such as shift members  120 ,  122 ) such that the shift finger engaging portion  98  may be interposed between two adjacent shift members. 
     With reference to  FIGS. 6-15 , the shifting of the transmission  24  will be described in greater detail in relation to the shift finger  96 .  FIG. 6  illustrates a neutral configuration for the shift control system  26  is in a neutral configuration where the shift members  120 ,  122 ,  124 ,  126  are aligned when viewed in the second generally orthogonal direction SD and the shift clutches  82 ,  84 ,  86 ,  88  are disengaged and will not transmit any appreciable amount of torque between the prime mover  22  and the output member  32 . 
     The shift finger  96  is in a first engaged configuration when the shift finger  96  may be moved in the first generally orthogonal direction FD such that the shift finger engaging portion  98  contacts the first shift member  120  ( FIG. 16 ). The shift finger  96  is in a second engaged configuration when the shift finger  96  may be moved in the first generally orthogonal direction FD such that the shift finger engaging portion  98  contacts the second shift member  122  ( FIGS. 7 and 8 ). The shift finger  96  is in a third engaged configuration when the shift finger  96  may be moved in the first generally orthogonal direction FD such that the shift finger engaging portion  98  contacts the third shift member  124  ( FIGS. 3 ,  4 ,  11  and  12 ). The shift finger  96  is in a fourth engaged configuration when the shift finger  96  may be moved in the first generally orthogonal direction FD such that the shift finger engaging portion  98  contacts the fourth shift member  126  ( FIGS. 13-15 ). 
     The shift finger is in an intermediate configuration when the shift finger engaging portion  98  may be moved in the first generally orthogonal direction FD such that the shift finger engaging portion  98  would not contact any shift member, such as shift members  120 ,  122 ,  124 ,  126  ( FIGS. 5 ,  6 ,  9 , and  10 ). In the intermediate configuration of  FIGS. 5 ,  6 ,  9 , and  10 , the shift finger engaging portion  98  may be moved in the first generally orthogonal direction FD when interposed between adjacent shift members. As best seen in the specific configuration of  FIG. 5 , the shift finger engaging portion  98  is moved differing distances, depending upon the relative positions of the shift members  120 ,  122 ,  124 ,  126 . That is, for example, the distance between the second shift member distal surface  210  and the third shift member distal surface  220  (measured in the first generally orthogonal direction FD) is a first shift distance, while the distance between the third shift member distal surface  220  and the fourth shift member distal surface  230  (measured in the first generally orthogonal direction FD) is a second shift distance. 
     Complementary to the discussion above describing the shifting of the transmission  24  from the neutral configuration to the first speed ratio configuration to the second speed ratio configuration, the following will present the concurrent movement of portions of the shift control system  26 . With the shift control system  26  in the neutral configuration (schematically illustrated in  FIGS. 6 and 7  and including all configurations where the shift members  120 ,  122 ,  124 ,  126  are aligned as in  FIGS. 6 and 7 ), the transmission  24  is in the neutral configuration schematically illustrated in  FIG. 2 . The shift control system  26  is directed by the ECU  30  to shift the transmission into the first speed ratio configuration. Generally, upon startup of the prime mover  22 , the ECU  30  will detect the position of clutches C 1 , C 2 ,  82 ,  84 ,  86 , and  88  to determine the transmission  24  and the shift control system  26  configuration. 
     The shift control system  26  moves the shift finger engaging portion  98  in the second generally orthogonal direction SD (if necessary) to the position illustrated in  FIG. 7 . Confirming that the first main clutch C 1  is disengaged (which may be performed by the ECU  30 ), the shift control system  26  moves the shift finger engaging portion  98  in the first generally orthogonal direction FD (as the finger proximal shift surface  182  contacts the second shift member proximal surface  212 ) from the position illustrated in  FIG. 7  to the position illustrated in  FIG. 8  (a distance generally equal to the first shift distance) to place the transmission  24  and the shift control system  26  in the first speed ratio configuration, as the second shift clutch  84  engages the first speed output gear  62 . The first main clutch C 1  is then engaged to rotatably connect the output member  46  with the countershaft  44 . 
     When a shift from the first speed ratio configuration to the second speed ratio configuration is desired, the ECU  30  will confirm that the clutches  82 ,  86 , and  88  are not engaged and will direct the shift control system  26  to move the shift finger engaging portion  98  in the second generally orthogonal direction SD from the position of  FIG. 8  to the intermediate configuration of  FIG. 9 , then move the shift finger engaging portion  98  in the first generally orthogonal direction FD, while remaining in the intermediate configuration, to the position schematically illustrated in  FIG. 10  (a distance generally equal to about the first shift distance), then move the shift finger engaging portion  98  in the second generally orthogonal direction SD from the intermediate configuration of  FIG. 10  to the fourth engaged configuration of  FIG. 14 , then move the shift finger engaging portion  98  in the first generally orthogonal direction FD such that the finger distal shift surface  180  of the shift finger engaging portion  98  contacts the fourth shift member distal surface  230  and the fourth shift clutch  88  is engaged with the second speed output gear  70  ( FIG. 15 ). To shift from the first gear to the second gear, the first main clutch C 1  is disengaged as the second main clutch C 2  is engaged. 
     When a shift from the second speed ratio configuration to the third speed ratio configuration is desired, the ECU  30  will confirm that the clutches  82 ,  84 , and  86  are not engaged and will direct the shift control system  26  to move the shift finger engaging portion  98  in the second generally orthogonal direction SD from the position of  FIG. 15  (while not moving the fourth shift member  126 ) to an intermediate configuration where the shift finger engaging portion  98  is positioned between the third shift member  124  and the fourth shift member  126 , then move the shift finger engaging portion  98  in the first generally orthogonal direction FD, while remaining in the intermediate configuration, to a position between the third shift member  124  and the fourth shift member  126  such that the shift finger engaging portion  98  may be moved in the first generally orthogonal direction FD and be interposed between the surfaces  220 ,  222  of the third shift member  124  (similar to  FIG. 12 ). The shift finger engaging portion  98  is then moved in the second generally orthogonal direction SD while being at least partially interposed between the surfaces  220 ,  222  of the third shift member  124 , to a position where the shift finger engaging portion  98  is positioned between the second shift member  122  and the third shift member  124  (similar to  FIG. 10 ). The shift finger engaging portion  98  is then moved in the first generally orthogonal direction FD from the intermediate configuration (generally of  FIG. 10 ) to a position generally illustrated in  FIG. 9 , where the shift finger engaging portion  98  may be moved in the second generally orthogonal direction SD and be interposed between the surfaces  210 ,  212  of the second shift member  122  (similar to  FIG. 8 ). The shift finger engaging portion  98  is then moved in the second generally orthogonal direction SD and interposed between the surfaces  210 ,  212  of the second shift member  122  (into the second engaged configuration). The shift finger engaging portion  98  is then moved in the first generally orthogonal direction FD about a distance equal to the first shift distance, such that the finger distal shift surface  180  of the shift finger engaging portion  98  contacts the second shift member distal surface  210 , moving the second shift member  122  to about the position of  FIG. 7 , and the shift clutch  84  is disengaged with the first speed output gear  62  (thereby disengaging the first gear). The shift finger engaging portion  98  is then moved in the second generally orthogonal direction SD from the second engaged configuration to the third engaged configuration (while not moving the second shift member  122 ) through an intermediate configuration where the shift finger engaging portion  98  is positioned between the second shift member  122  and the third shift member  124 . That is, the shift finger engaging portion  98  is moved from a position where the shift finger engaging portion  98  is interposed between the surfaces  210 ,  212  of the second shift member  122  to a position where the shift finger engaging portion  98  interposed between the surfaces  220 ,  222  of the third shift member  124 . The shift finger engaging portion  98  is then moved in the first generally orthogonal direction FD about a distance equal to the first shift distance, such that the finger proximal shift surface  182  of the shift finger engaging portion  98  contacts the third shift member proximal surface  222 , moving the third shift member  124  to a position (illustrated generally in  FIG. 5 ) where the third shift clutch  86  is engaged with the third speed output gear  64  (thereby engaging the third gear). To shift from the second gear to the third gear, the second main clutch C 2  is disengaged as the first main clutch C 1  is engaged. 
     The preceding description has been presented only to illustrate and describe exemplary embodiments of the methods and systems of the present invention. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. It will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. The invention may be practiced otherwise than is specifically explained and illustrated without departing from its spirit or scope. The scope of the invention is limited solely by the following claims.