Abstract:
A multiplate torque converter clutch system, which is adapted for installation in torque converters of different automatic transmission manufacturers, namely, BORG WARNER, ALLISON, FORD, GENERAL MOTORS, and CHRYSLER transmissions. The present multiplate torque converter clutch system is provided in kit format including a hybrid lock-up piston/damper plate subassembly, multiple clutch plates including friction rings, a set of outer damper springs, and a set of inner damper springs. The present multiplate torque converter clutch system also includes a torque converter cover subassembly and a turbine hub subassembly configured to adapt the present torque converter clutch system to different vehicle engines and transmissions respectively. The hybrid lock-up piston/damper plate subassembly can be tuned to match a peak engine torque value by changing the number of damper springs. Advantageously, the present hybrid lock-up piston/damper plate subassembly is disassembled by removal of a single retaining ring to facilitate changes to the damper springs.

Description:
BACKGROUND OF INVENTION 
     The present invention relates to automatic transmissions for land vehicles and, more particularly, to a universal torque converter clutch system including a hybrid lock-up piston/damper plate subassembly, which is designed for installation in the torque converters of automatic transmissions from various manufacturers, namely, BORG WARNER, ALLISON, FORD, GENERAL MOTORS, and CHRYSLER or other similar automatic transmissions. 
     For purposes of this application the term “hybrid” will be understood to define the present lock-up piston/damper plate subassembly having components with features and characteristics derived from both the original equipment manufacture lock-up piston and damper plate components as provided with BORG WARNER, ALLISON, FORD, GENERAL MOTORS, and CHRYSLER transmissions (hereinafter “the subject transmissions”). 
     The torque converter of an automatic transmission replaces the clutch used in manual transmissions. It is the primary component for transmittal of power between the engine and the transmission in an automotive vehicle. The basic principle of torque converter operation can be observed by placing the blades of two electric fans opposite each other and turning on one of the fans. If one of the fans is turned on, the force of the air column produced will act upon the motionless blades of the other fan, which will begin turning and eventually reach a speed approaching the speed of the powered fan. The torque converter employs an analogous mechanism using automatic transmission fluid (hereinafter “ATF”) to provide a fluid coupling between the engine and the transmission of an automobile, which provides for a smooth conversion of torque from the engine to the mechanical components of the transmission. 
     During the torque converter lock-up cycle, the torque converter clutch  120  (see  FIG. 1 ) is applied to eliminate the slippage that occurs through the fluid coupling and to provide a direct mechanical drive for efficient transfer of engine torque to the drive wheels. More particularly, during the lock-up cycle the torque converter clutch  120  is shifted axially forward by ATF pressure and frictionally engages an inner surface of the torque converter cover  125  to affect such direct mechanical drive. The torque converter cover  125  rotating at engine speed instantaneously engages the damper plate assembly  146  (see  FIG. 3 ) when actuated by the lock-up piston  142 , which serves to transmit the rotational torque of the engine directly to the transmission. The damper plate assembly  146  functions to absorb the sudden impact of such direct mechanical drive engagement to prevent damage to the turbine shaft and also to the friction materials within the torque converter clutch  120 . 
     Still referring to  FIG. 3  the prior art damper plate assembly  146  includes an array of radially disposed damper springs  147  having a predetermined strength (i.e. spring rate), which are permanently captured in the riveted construction of the prior art damper plate assembly. The strength of such damper springs  147  is factored into the design of the damper plate assembly  146  based on the factory specified peak engine torque generated in a given vehicle engine, which is critical to the proper function of the lock-up clutch. 
     However, in the automotive aftermarket various engine-tuning modules are marketed for truck engines utilizing the subject transmissions, which deliver the most powerful, street-legal tuning available for towing the maximum loads allowed by the vehicle manufacturer. At such higher horsepower gains the original equipment manufacture (hereinafter “OEM”) lock-up clutch  120  including the damper plate assembly  146  is often overmatched and prone to failure. 
     More particularly, it is well known in the industry that when the subject transmissions, which were initially designed to operate behind a truck engine manufactured to a factory torque specification, are utilized in a higher horsepower application, the spring strength of the OEM damper plate assembly  146  is inadequate and the damper springs  147  may be compressed beyond their working limits. This results in mechanical damage to the damper plate assembly  146 , friction rings  130 , and also to the turbine shaft spline as at  153  ( FIG. 1 ) during the torque converter lock-up cycle and other peak torque events. 
     Thus, the present invention has been developed to resolve this problem and other shortcomings of the prior art. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is a universal multiplate torque converter clutch system, which is designed for installation in automatic transmissions of different vehicle manufacturers, namely, the subject transmissions, and other similar automatic transmissions. 
     The present universal multiplate torque converter clutch system is provided in kit format including a hybrid lock-up piston/damper plate subassembly, multiple clutch plates including friction rings, at least two sets of damper springs, a spring retainer, a retaining ring (i.e. snap ring), a turbine hub, a front cover, a front cover bushing and ATF seals necessary to adapt the present clutch system to a specific vehicle engine and automatic transmission. 
     Advantageously, the present invention provides for tuning of the present hybrid lock-up piston/damper plate subassembly to match peak engine torque by changing the number of damper springs therein. To this end the hybrid lock-up piston/damper plate subassembly is conveniently disassembled by the removal of a single snap ring in comparison to the permanent riveted construction of the OEM damper plate assembly. Further, the present universal multiplate torque converter clutch system is suitable for both diesel and gasoline engine applications. 
     There has thus been outlined, rather broadly, the important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     Other features and technical advantages of the present invention will become apparent from a study of the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the present invention are set forth in the appended claims. The invention itself, however, as well as other features and advantages thereof will be best understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures, wherein: 
         FIG. 1  is a partial longitudinal cross-section of a torque converter assembly including an impeller assembly, a turbine assembly, and a torque converter cover and is labeled Prior Art; 
         FIG. 2  is an exploded perspective view of the torque converter assembly of  FIG. 1  including the turbine, stator, and impeller assemblies illustrating the flow of automatic transmission fluid therein and is labeled Prior Art; 
         FIG. 3  is an enlarged partial longitudinal cross-section of the torque converter assembly of  FIG. 1  showing further details thereof and is labeled Prior Art; 
         FIG. 4  is a longitudinal cross-section of a FORD E40D torque converter cover including a torque converter lock-up clutch wherein the present invention is utilized and is labeled Prior Art; 
         FIG. 5  is a top plan view of the damper plate assembly of a FORD E4OD lock-up clutch and is labeled Prior Art; 
         FIG. 6  is a perspective view of a torque converter cover for the FORD E4OD transmission showing an array of embossments formed therein and is labeled Prior Art; 
         FIG. 7  is a longitudinal cross-section of a torque converter assembly showing the present universal multiplate torque converter clutch system of the present invention; 
         FIG. 8  is a top plan view of the present universal multiplate torque converter clutch showing the hybrid lock-up piston/damper plate subassembly of the present invention; 
         FIG. 9A  is a top plan view of the piston carrier of the present invention; 
         FIG. 9B  is a longitudinal cross-section of the piston carrier shown in  FIG. 9A ; 
         FIG. 10A  is a top plan view of one of an identical pair drive plates of the present invention; 
         FIG. 10B  is a longitudinal cross-section taken along section line  10 B- 10 B of  FIG. 10A ; 
         FIG. 11A  is a top plan view of a clutch hub of the present invention; 
         FIG. 11B  is a longitudinal cross-section taken along section line  11 B- 11 B of  FIG. 11A ; 
         FIG. 12A  is a top plan view of the spring retainer of the present invention; 
         FIG. 12B  is a longitudinal cross-section of the spring retainer of  FIG. 12A  taken along section line  12 B- 12 B; 
         FIG. 13  is an exploded cross-sectional view of the components of the hybrid lock-up piston/damper plate subassembly of the present invention; 
         FIG. 14  shows a reference table of engine torque values (expressed in foot-lbs.) for determining the number of damper springs to be installed in the hybrid lock-up piston/damper plate subassembly of the present invention; 
         FIG. 15A  is a top plan view of the turbine tub of the present invention; 
         FIG. 15B  is a longitudinal cross-section of the turbine hub of  FIG. 15A  taken along section line  15 B- 15 B; 
         FIG. 16  is a top plan view of a primary clutch plate of the present invention; 
         FIG. 17  is a top plan view of a secondary clutch plate of the present invention; 
         FIG. 18A  is a top plan view of the front cover of the present invention; 
         FIG. 18B  is a longitudinal cross-section of the front cover of  FIG. 18A  taken along section line  18 B- 18 B; 
         FIG. 19A  is a top plan view of the front cover bushing of the present invention; 
         FIG. 19B  is a side elevation view of the present front cover bushing rotated 90° from the position shown in  FIG. 19A ; and 
         FIG. 20  is an exploded view illustrating the assembly of the cover, primary clutch plate, secondary clutch plate, and the hybrid lock-up piston/damper plate subassembly of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Prior to describing the present invention in detail, it may be beneficial to briefly review the structure and function of a prior art torque converter and torque converter clutch of an automatic transmission in more detail. With further reference to the drawings there is shown therein a partial, cross-sectional view of such a prior art torque converter assembly, indicated generally at  100  and illustrated in  FIG. 1 , which is the primary component for transmittal of power between the engine and the automatic transmission or transaxle in an automotive vehicle. The torque converter assembly  100  provides for a smooth conversion of torque from the vehicle&#39;s engine to the mechanical components of the transmission and also functions to multiply torque generated by the engine enabling the vehicle to achieve additional performance when necessary. 
     Torque converter assembly  100  is comprised of the following main sub-assemblies: (1) an impeller assembly, indicated generally at  105 , which is the driving member; (2) a turbine assembly, indicated generally at  110 , which is the driven member; (3) a stator assembly, indicated generally at  115 , (4) a lock-up clutch assembly, indicated generally at  120 , which is attached to the turbine assembly  110  to enable direct mechanical drive; and (5) a torque converter cover, indicated generally at  125 , which is typically welded as at  121  to the impeller assembly  105 . 
     Cover  125  is connected to the engine flywheel (not shown) by threaded studs  126  supported by stud flanges  126   a , which are attached to the cover so that it will rotate at engine speed. When the engine is running, the impeller assembly  105  acts as a centrifugal pump by picking up ATF at its center and discharging it at its rim between the impeller blades  103  as more clearly shown in  FIG. 2  (see directional arrows  107 ) establishing toroidal ATF out-flow passages  106  in fluid communication with toroidal ATF in-flow passages  108  defined by turbine blades  113 . The force of the ATF hits the turbine blades  108  and causes turbine assembly  110  to rotate as indicated (see directional arrows  109 ). As the engine and impeller assembly  105  increase in speed, so does the turbine assembly  110 . 
     As shown in further detail in  FIG. 3 , the prior art lock-up piston  142  including peripheral teeth  143  engages inwardly extending ribs  111  formed on the inner surface of cylindrical portion  125   a  of cover  125  and also attaches to the turbine hub  101  to provide a mechanical coupling of the engine to the transmission during the torque converter lock-up cycle. When the lock-up clutch  120  is applied, the slippage that occurs through the fluid coupling is eliminated thereby providing a direct mechanical drive for efficient transfer of engine torque to the drive wheels. 
     Referring again to  FIGS. 1-2 , a stator assembly  115  is located between the impeller assembly  105  and the turbine assembly  110  and is mounted on a stator carrier  114  that is connected to an inner race  119  through a one-way roller clutch  116 , which allows rotation in only one direction. The function of the stator assembly  115  is to redirect fluid returning from the turbine assembly  110  (see directional arrows  107 ) to assist the engine in turning the impeller assembly  105 . 
     The impeller assembly  105  is supported by an impeller hub  104  ( FIG. 1 ), which extends from the impeller assembly  105  along its longitudinal axis and engages the hydraulic pump (not shown) in the transmission. The turbine shaft  151  ( FIG. 1 ) extends through the impeller hub  104  and delivers power to the transmission. 
     When the lock-up clutch  120  is installed within the torque converter cover  125  as most clearly shown in  FIG. 3 , a clutch release chamber  170  is formed between the cover  125  and the lock-up clutch  120 . When the fluid pressure behind the lock-up clutch  120  in the clutch apply chamber  180  exceeds the pressure in the release chamber  170 , the lock-up cycle is initiated and the clutch is shifted forward to engage the cover  125  establishing a mechanical torque flow path coupling the engine flywheel to the transmission. 
     Referring to  FIG. 4  the latest versions of the subject transmissions use a more sophisticated converter clutch system that is used in virtually all transmissions being produced for automobiles today (i.e. the electronic/hydraulic multiplate torque converter clutch assembly). The lock-up cycle in such an electronic converter clutch systems is controlled by a microprocessor within the vehicle&#39;s onboard computer (not shown). 
     For purposes of explanation the mechanical components of such an electronic/hydraulic torque converter clutch system for a FORD E4OD transmission, illustrated in  FIG. 4  and indicated generally at  200 . In this embodiment a so-called multiplate lock-up clutch assembly  200  includes a piston  220 , a splined friction plate  224 , and a damper plate assembly, indicated generally at  240 , installed within the front cover  225  just forward of the turbine assembly. Friction plate  224  includes friction material (i.e. a friction ring  222 ) on its aft surface, which contacts the adjacent forward surface of the piston  220  during the lock-up cycle. Damper plate  244  also has friction rings  22 T on both its forward and aft surfaces, which engages a lock-up surface  245  formed on the radial wall  223  of cover  225  during the lock-up cycle as more clearly shown in  FIG. 6 . 
     In a multiplate lock-up clutch of the type shown in  FIG. 4 , the damper plate  244  also includes damper springs  242  disposed within radially spaced spring pockets  246  to absorb the impact of lock-up clutch engagement. It will be appreciated that the prior art damper plate  244  is a riveted construction wherein damper springs  242  are permanently captured in position by installation of rivets  249  ( FIG. 5 ), which extend through the damper plate  244  and a spring retainer plate  241 . 
     In the electronic/hydraulic converter clutch system shown in  FIG. 4 , when the vehicle is cruising and lock-up is appropriate, an electric solenoid is energized which opens the converter clutch control valve (not shown) increasing ATF pressure in the apply chamber  280 . This allows ATF pressure to act upon the piston  220  to actuate the lock-up clutch. Friction plate  224  is guided forward in an axial direction by an array of teeth  247  formed about the periphery thereof as shown in  FIG. 5 . In the subject transmissions teeth  247  on the friction plate  2244  ( FIG. 5 ) traverse an array of mating teeth  274  formed in the cover  225  ( FIG. 6 ). Friction plate  224  together with piston  220  act upon the damper assembly  240 , which, in turn, is forced against the lock-up surface  245  on the front cover  225 . Lock-up piston  220  is also connected to the turbine hub  201 , which drives the turbine shaft (not shown) and, thus, a direct mechanical link between the engine and transmission is established. 
     Still referring to  FIG. 4  when converter lock-up is no longer required, a port opens that allows pressurized ATF to flow into the clutch release chamber  270  thereby releasing the lock-up clutch  200 . ATF then flows out of the apply chamber  280  and the piston  220  moves away from the lock-up surface  245  re-establishing the fluid coupling. 
     Referring again to  FIG. 5  the prior art damper plate assembly  240  also includes an array of radially disposed damper springs  242  having a predetermined strength (i.e. spring rate), which are permanently captured within spring pockets  246  by the riveted construction of the damper plate assembly. The strength of damper springs  242  is also factored into the design of the damper plate assembly  240  based on the torque generated by a particular vehicle&#39;s engine and is critical to the proper function of the lock-up clutch. 
     However, in the automotive aftermarket engine tuning modules are marketed for both diesel and gasoline truck engines, which deliver the most powerful, street-legal tuning available for towing the maximum loads allowed by the vehicle manufacturer. At such higher horsepower gains the OEM lock-up clutch  200  including the damper plate assembly  240  is mismatched against such increased engine torque and prone to failure during peak torque events. 
     More particularly, when the subject transmissions are utilized in such higher horsepower applications, the strength of damper springs  242  in the OEM damper plate assembly  240  is insufficient and the damper springs can be compressed beyond their working limits (i.e. springs  242  “bottom out” in the spring pockets  246 ) during converter lock-up. This results in mechanical damage to the damper plate assembly  240 , friction rings  222 ,  222 ′, and also to the turbine shaft  151  during the lock-up cycle. 
     Thus, the present invention has been developed to resolve this problem and will now be described. Referring to  FIG. 7  there is shown therein a universal multiplate torque converter clutch system in accordance with the present invention, indicated generally at  10 . The present universal clutch system  10  is comprised of the following subassemblies and components: (1) a hybrid lock-up piston/damper plate subassembly, indicated generally at  15 ; (2) a primary clutch plate, indicated generally at  25 ; (3) a secondary clutch plate, indicated generally at  30 ; (4) a turbine hub subassembly, indicated generally at  35 ; and (5) a front cover subassembly, indicated generally at  50 . 
     As more clearly shown in  FIG. 8 , the present hybrid lock-up piston/damper plate subassembly  15  further comprises: (a) a piston carrier  60 ; (b) a pair of drive plates  65  (i.e. only top drive plate  65  shown); (c) a clutch hub  70 ; (d) a set of inner damper springs  45 ; (e) a set of outer damper springs  55 ; (f) a spring retainer  80 ; and (g) a retaining ring  75 , which will now be described in further detail. 
     With reference to  FIGS. 9A and 9B  there is shown therein a piston carrier  60 , which is a generally dish-shaped component having a center opening  62 . Piston carrier  60  is fabricated from a steel forging in accordance with American Iron and Steel Institute (hereinafter “AISI”)  1045  or other suitable material. Piston carrier  60  includes an external spline, indicated generally at  63 , having a plurality of teeth  64  formed thereon for mating engagement with an internal spline  63 ′ including mating teeth  64 ′ formed in clutch plate  25  ( FIG. 16 ). Center opening  62  ( FIG. 9A ) of piston carrier  60  engages a mating diameter  62 ′ of turbine hub  35  during assembly and thereby surrounds TEFLON seal  40  including an underlying O-ring  40 ′ disposed in groove  36  ( FIG. 15B ). 
     Still referring to  FIGS. 9A and 9B , piston carrier  60  includes an integral receptacle  90  wherein the components of the present hybrid piston/damper plate assembly  15  are installed. It can be seen that receptacle  90  includes a plurality of semicircular notches  92  machined therein. Semicircular notches  92  are formed in a symmetrical pattern about the circumference of receptacle  90  to receive mating semicircular protuberances  92 ′ formed on a matched pair of drive plates  65  provided with the present hybrid piston/damper plate subassembly  15  as shown in  FIGS. 10A and 10B . In this manner rotation of the drive plates  65  is precluded within the receptacle  90  after installation. Each drive plate  65  includes an array of damper spring pockets  66 , which receive damper springs  45 ,  55  ( FIG. 8 ) therein. It will be appreciated that during assembly of the hybrid lock-up piston/damper plate  15 , each array of damper spring pockets  66  within the drive plates  65  is arranged in alignment to receive damper springs  45 ,  55 . 
     Referring to  FIGS. 11A and 11B  a clutch hub  70  is also provided for installation within receptacle  90 . In the present clutch system, clutch hub  70  is captured between the pair of drive plates  65  (see  FIG. 7 ) during assembly. Clutch hub  70  also includes an array of damper spring pockets  76 , which function to receive damper springs  45 ,  55  therein. It will be understood that during assembly clutch hub  70  is rotated to the same angular orientation as drive plates  65  within receptacle  90  such that damper spring pockets  66 ,  76  are positioned in axial alignment to receive damper springs  45 ,  55 . 
     After clutch hub  70  is installed as shown in  FIGS. 7 and 8 , it will be appreciated that the clutch hub is imparted with up to 8.4° angular rotation relative to the fixed drive plates  65  against the force of damper springs  45 ,  55  to dampen clutch engagement during the lock-up cycle. To this end it can be seen that clutch hub  70  also includes an array of weight reducing holes  77  to reduce its mass. 
     A spring retainer  80  fabricated from stainless steel sheet in accordance with the American Society of Testing and Materials (hereinafter “ASTM”) specification A-177 is provided in the configuration shown in  FIGS. 12A and 12B . Spring retainer  80  includes a plurality of spring tabs  82  bent upwardly at approximately 45 degrees, which are also positioned in overlying relation to outer damper springs  55  during assembly as most clearly shown in  FIG. 8 . 
     Advantageously, a single retaining ring or so-called snap ring  75  also fabricated from stainless steel sheet in accordance with ASTM specification A-177 is utilized to secure the components of the present hybrid lock-up piston/damper plate assembly  15  (i.e. drive plates  65 , clutch hub  70 , damper springs  45 ,  55 , spring retainer  80 ) within piston carrier  60  ( FIG. 8 ). Snap ring  75  is installed behind lip  91  within the interrupted groove  93  formed in receptacle  90  as most clearly shown in  9 B. A commercially available snap ring  75 , namely, part #VH-825 manufactured by the Smalley Steel Ring Company, Lake Zurich, Ill. 60047, is suitable for this purpose. 
     An innovative feature of the present invention permits the hybrid lock-up piston/damper plate subassembly  15  to be tuned to match the specific peak torque of a given vehicle&#39;s engine wherein the present universal clutch system  10  is to be utilized. Initially, it will be understood that the hybrid lock-up piston/damper plate assembly  15  of the present invention is provided with the entire complement of ten pairs dampers springs  45 ,  55  installed ( FIG. 8 ). 
     With reference to  FIG. 13 , tuning the hybrid lock-up piston/damper plate subassembly  15  requires changing the number of inner damper springs  45  to match peak engine torque. To accomplish this retaining ring  75  is initially removed from groove  93  with a suitable tool. Next, the spring retainer  80  and the upper drive plate  65  are removed and set aside. Next, damper springs  45 ,  55  are removed and/or reinstalled to match engine torque (i.e. expressed in foot-lbs.) in accordance with Table 1 ( FIG. 14 ). Note that only an even number of damper springs  45 ,  55  is utilized and that inner damper springs  45  must be installed in a symmetrical pattern 180° apart within outer damper springs  55 . This prevents binding of the present hybrid lock-up piston/damper plate subassembly  15  and imbalance of the subassembly during operation. Next, the upper drive plate  65 , spring retainer  80 , and snap ring  75  are reassembled as described hereinabove. Finally, it is recommended that the present hybrid lock-up piston/damper plate subassembly  15  be balanced as a separate unit before being further assembled into the torque converter. 
     Since such rotational balancing procedures for automotive components are well known to those skilled in the art, further detailed discussion is not deemed necessary. 
     With reference to  FIGS. 15A and 15B , there is shown therein the present turbine hub subassembly, indicated generally at  35 . The turbine hub  33  is a generally cylindrical component including an integral perpendicular flange  38 , which includes a radial array of rivet holes  39  drilled therein. Turbine hub  33  also includes an external spline  72 ′ for engagement with an internal spline  72  formed in the clutch hub  70  ( FIGS. 11A and 11B ). In addition, turbine hub  33  includes an internal bore  31  wherein an internal spline  34  is formed, which receives a mating turbine shaft  151 ′ ( FIG. 7 ) at assembly. 
     To install the present turbine hub  33  the OEM rivets  275  attaching the OEM turbine hub  201  ( FIG. 4 ) are initially removed and the OEM turbine hub  201  is separated from the OEM turbine  110 . Next, the OEM turbine  110  is cleaned and inspected. If any turbine blades  113  are loose, the blades are repaired by brazing/welding or a different OEM turbine  110  is obtained for reassembly. Next, the present turbine hub  33  is positioned within the turbine  110  in replacement of OEM turbine hub  201  and new rivets  275  are installed. Next, a TEFLON seal  40  with an underlying O-ring  40 ′ are installed within groove  36  in the journal diameter  62 ′ of the turbine hub  33 . In the embodiment shown in  FIG. 15B , a new radial lip seal  57  is installed within the bore  31  of turbine hub  33 . It will be understood that some alternative embodiments of the present invention, namely, the FORD E4OD and GM 4L80E cover assemblies do not utilize a radial lip seal  57 . 
     It will be understood by those skilled in the art that the turbine hub  33  for each kit provided in the present universal clutch system for the subject transmissions differs slightly in its size and configuration, namely, in the flange  38 , in the internal bore  31 , and in the internal spline  34 , which are dimensioned to fit the mating parts of the subject transmissions. 
     Referring to  FIG. 16  the present primary clutch plate  25  is fabricated from sheet steel in accordance with AISI 1050 or other suitable material and includes friction rings  28  bonded to both the forward and aft facing surfaces thereof, which engage a mating contact surface  52  within front cover  50  ( FIG. 18B ) and also a mating surface of the present secondary clutch plate  30  ( FIG. 17 ) respectively during the lock-up cycle. 
     With reference to  FIG. 17  the present secondary clutch plate  30  is also fabricated from sheet steel in accordance with AISI 1050 or other suitable material and includes a friction ring  28 ′ on the aft facing surface thereof, which engages a mating forward facing surface of piston carrier  60  during the lock-up cycle. Secondary clutch plate  30  also includes an external spline, indicated generally at  54 ′, including a plurality of teeth  56 ′ formed thereon for mating engagement with an internal spline  54  including mating teeth  56  formed in front cover subassembly, indicated generally at  50  ( FIG. 18B ). 
     As shown in  FIGS. 18A and 18B  cover housing  59  is a bowl-shaped component machined from a steel forging in accordance with AISI specification 1026. Cover housing  59  functions to enclose the present universal torque converter clutch system and to attach the torque converter to the vehicle&#39;s engine via flexplate  85  ( FIG. 7 ). More particularly, a forward facing surface  53  of cover housing  59  includes a plurality of integral bosses  26  having threaded holes  27  formed therein. Cover housing  59  also includes a cover pilot  37  projecting from surface  53  ( FIG. 18B ) which functions to locate the front cover in coaxial relation to the engine crankshaft (not shown). Threaded holes  27  receive machine bolts  29 , which attach the engine flexplate  85  to the cover housing  50  ( FIG. 7 ). In the present invention it will be appreciated that because the present universal clutch system  10  is designed to be installed in different vehicles utilizing the subject transmissions, the pattern of threaded holes  27  and, thus, the construction of cover housing  59  varies to facilitate installation in the subject transmissions. 
     In the embodiment shown in  FIG. 18B , cover housing  59  is provided with a cover bushing  51 , which supports and engages a mating bearing journal  51 ′ formed on turbine hub  33 . Bushing  51  is fabricated from steel in accordance with the Society of Automotive Engineers (SAE) specification 799 or another suitable material in the configuration shown in  FIGS. 19A and 19B . It will be understood that some alternative embodiments of the present invention, namely, the FORD E40D, ALLISON 1000, and GM 4L80E cover assemblies do not utilize a cover bushing  51 . 
     In a method of the present invention, a cover housing  59  with a cover bushing  51  installed ( FIG. 18B ) is selected based on the particular vehicle engine and transmission to be utilized. Next, a turbine hub  33  with the correct internal spline  34  and flange  38  is selected based on the given turbine  110  and turbine shaft  151  to be utilized and, thereafter, is installed on turbine as described hereinabove. Next, the present hybrid lock-up piston/damper plate subassembly  15  including the damper springs  45 ,  55  specified in Table 1 is assembled based on the engine&#39;s peak torque output as described hereinabove and is separately balanced using known techniques. Thereafter, the hybrid lock-up piston/damper plate subassembly  15 , primary clutch plate  25 , and secondary clutch plate  30  are installed within cover subassembly  50  in coaxial relation to longitudinal axis -A- as shown in  FIG. 20 . Next, the energizer O-ring  40 ′ and the TEFLON seal  40  are installed within groove  36  and the radial lip seal  57  (when applicable) is installed within the bore  31  to complete the turbine hub subassembly  35 . Next, the internal spline  72  of the clutch hub  70  is guided axially into mating engagement with the external spline  72 ′ of the turbine hub subassembly  35  to the position shown in  FIG. 7 . Thereafter, the cover subassembly  50  is welded about its periphery at the junction with the OEM impeller assembly  105  as at  95 . Next, the assembled torque converter is guided axially into mating engagement with the turbine shaft  151 ′ and stator support shaft  152  ( FIG. 7 ) of the transmission. Thereafter, flexplate  85  is attached to the engine crankshaft (not shown). Next, the transmission and torque converter assembly are installed by guiding the cover pilot  37  into engagement with the crankshaft. Thereafter, cover subassembly  50  is attached to flexplate  85  by machine bolts  29  to complete the installation ( FIG. 7 ). 
     Although not specifically illustrated in the drawings, it should be understood that additional equipment and structural components will be provided as necessary and that all of the components described above are arranged and supported in an appropriate fashion to form a complete and operative Universal Multiplate Torque Converter Clutch System and Method of Use incorporating features of the present invention. 
     Moreover, although illustrative embodiments of the invention have been described, a latitude of modification, change, and substitution is intended in the foregoing disclosure, and in certain instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of invention. 
     Having described preferred embodiments of our invention, what we desire to secure by U.S. Letters Patent is: