Abstract:
An adaptor for an older Corvette drive train provides a structure for coupling the drive shaft extending from a front-mounted transmission to the differential of a C5 or C6 Corvette rear suspension in which the rear mounted transmission has been removed. A housing holds a stub shaft for rotation on front (outside) and rear (inside) bearings. The shaft has a coupling yoke mounted to its front end and engages the differential gearing at its other (rear) end. The housing mounts to the differential at the five mounting points of the removed transmission. A bracket which attaches to frame mounts can be mounted to either the top or bottom front (outside) face of the housing, depending upon the suspension-to-frame geometry. A circular flange on the shaft positions and holds the inside bearing and a rearward extending boss on the yoke positions and holds the outside bearing. A crushable tubular spacer fits over a portion of the shaft and holds the front and rear bearings apart during assembly and while the shaft assembly is drawn up. Two grease ports and fittings access the interior of the peripheral sealing ring to meet and seal the differential opening.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention is related to automotive drive train adaptors, specifically an adaptor which permits the mating of drive train components not normally designed to be connected. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention is directed to an adaptor which permits a Chevrolet Corvette C5 or C6 rear end assembly to be used in a rebuild of an older Corvette, such as a C1, C2, or C3 generation model. 
         [0003]    The Corvette has had six generations of vehicle design, typically known in the industry as C1 through C6, with the C1 being produced from 1953 to 1962, the C2 being produced from 1963 to 1967, the C3 being produced from 1968 to 1982, the C4 being produced from 1984 to 1996, the C5 being produced from 1997 to 2004, and the C6 being produced from 2005 to date. 
         [0004]    Each generation has maintained a fundamental design in its body, suspension, drive train, and engines, with changes being introduced from model year to model year within a generation to meet pollution requirements and changes in gasoline chemistry, to introduce appearance features, or to change engine and transmission specifications for sales promotion purposes. 
         [0005]    Through the years, the Corvette has become an American icon in the automotive industry. Attractive styling, sports car performance, and the use of fiberglass and plastic materials and exotic metals have attributed to a long standing desirability for older Corvette models among the public. 
         [0006]    An industry now exits in which older Corvettes are rebuilt or remanufactured from the ground up, i.e., from the frame outward. These rebuilt Corvettes often sell privately or at auction for in excess of $150,000 depending upon the model. The rebuilding of an older Corvette becomes the building of a Corvette as new parts from frame to suspension, to brakes, to engine, to drive train are introduced. Of necessity, the body remains, in whole or in part, from the original factory production. 
         [0007]    Through the various generations, changes have occurred in engines, drive trains, transmissions and suspensions. The C1 Corvette began with an inline six-cylinder engine, a two-speed automatic transmission, drum brakes and a solid rear axle with longitudinal leaf springs. A “small-block” (1955-1956) V8 engine and constant flow fuel injection was later introduced for the C1 Corvette for 1957-1961 in a 283 cu. in. engine. 
         [0008]    The C2 Corvette started with independent rear suspension, and a larger small-block (327 cu in) V8 engine with optional electronic ignition. As the C2 model years progressed with even higher horsepower with the larger (327 cu. in.) V8 engines and introduced two big-block (396 cu in and 427 cu in) V8 engines with modified automatic and manual transmissions and changes in carburation. These C2 big-block Corvettes are one of the most desirable antique vehicles in the United States. 
         [0009]    The C4 Corvette introduced a light-weight composite, transversely mounted, monoleaf front suspension that has been the standard for Corvettes ever since. A larger big-block (454 cu in) V8 engine with redesigned transmission was also introduced. The rear suspension remained with independent pivoting axels, leaf spring suspension similar to the design of the C2 Corvette. However, in later model years a cross-fire, throttle body injection engine was introduced, as well as plastic composite rear coil springs, thinner body panels, a catalytic converter, and an aluminum differential. More of the changes in model years addressed engine changes, engine modifications and transmission changes than changes in other portions of the vehicle. 
         [0010]    As with earlier generations, the C4 Corvette introduced a change in body style and looks. It also introduced changes in engines, carburetion/fuel injection and transmissions, as well as a transverse composite leaf spring in the rear. 
         [0011]    The C5 Corvette introduced major changes over the previous generations. Instead of a beam/rail type perimeter frame onto which the body was bolted, the C5 had a hydroformed perimeter frame integral with the body. The front and rear suspension assemblies which hold the engine, transmission, differential and suspension structure were joined by a center torque tube. The front suspension included alloy upper and lower control arms and steering knuckle, transverse monoleaf plastic composite spring, steel stabilizer bar, spindle offset and gas-pressurized shock absorbers positioned to operate within the cavities of the front wheels. The rear suspension was an independent 5-link design with toe-in and camber adjustment, alloy upper and lower control arms and knuckle, transverse monoleaf plastic composite spring, steel stabilizer bar and tie rods, tubular u-joint metal matrix composite drive shafts, and gas-pressurized shocks positioned to operate within the cavities of the rear wheels. The new geometry of the C5 rear suspension, including the new transverse leaf spring, offered greatly improved handling and lateral stability as well as providing an improved ride which reduced body rattles and squeaks. 
         [0012]    The rear suspension short-long arm and transverse leaf spring independent suspension configuration of the C5 was carried over into the C6 Corvette. However, the geometry of the cradles, control arms, knuckles, dampers and stabilizer bars was redesigned. These changes, including adjustments in various dimensions, have produced ever-improved ride and handing, less road noise, and better body control under greater lateral acceleration. 
         [0013]    Both the C5 and the C6 Corvette rear suspensions have height adjustments for raising or lowering the vehicle. It is well accepted in the marketplace that the C5 and C6 rear suspension designs are great improvements over the previous generations of Corvettes. Like the C4, the C5 and C6 suspensions continued with the leaf spring configuration, where the link arms permit the shock structure to extend into the interior space of the wheels. 
         [0014]    Like the C5 Corvette, the present C6 Corvette has its transmission mounted to the rear differential. This feature was introduced in an effort to obtain a 50-50 weight distribution in the vehicles. However, for body clearance when adapting a C5 or C6 rear suspension to an older C1 through C3 Corvette, the transmission must be mounted to the engine. 
         [0015]    While more and more Corvette enthusiasts are requesting C5 or C6 rear suspensions in their rebuilt older generation vehicles because of the better handling and ride, such crossover use in not possible without modification to the drive train and body. 
         [0016]    Older Corvettes can have one-piece drive shafts connecting the transmission to the rear differential, with the transmission being mounted at the engine. In order to use a C5 or C6 rear suspension on the older Corvettes it is necessary to eliminate the rear mounted transmission and provide an adaptor between the drive shaft and the differential. 
         [0017]    An object of the present invention is to provide an adaptor which mounts to an existing C5/C6 differential with the same sealing function as the C5/C6 transmission housing. 
         [0018]    A second object is to provide an adaptor which will handle the power from a modern “crate” engine, an original specification engine and transmission when coupled to the end of the drive shaft. 
         [0019]    A third is to provide an adaptor with a structure for more than one mounting configuration to accommodate different suspension height adjustments. 
         [0020]    Another object is to provide an adaptor with a structure for coupling to the end of the drive shaft from a front-mounted transmission. 
         [0021]    A further object is to provide an adaptor with sufficient lubrication to promote longevity of operation and reduce heat build-up. 
       SUMMARY OF THE INVENTION 
       [0022]    The objects of the present invention are realized in an adaptor which mounts to the rear differential of a C5 and C6 generation Corvette suspension assembly in place of the factory transmission housing normally attached to the differential, which has been removed. The adaptor includes a housing machined from a solid alloy block, with a front (outside) and rear (inside) faces. The inside face of the adaptor housing includes a toroidal-shaped flange which carries a peripherally mounted sealing ring, with the flange and sealing ring operating to seal the opening in the differential created upon the removal of the O.E.M. transmission housing. The outside (front) face of the adaptor housing has an outwardly projecting boss. A cylindrical cavity (bore) extends longitudinally through the housing. 
         [0023]    The housing supports a stub shaft which couples the end of the drive shaft from a front mounted engine/transmission to the rear differential. The shaft support within the housing includes a pair of bearings, a larger rear (inside) bearing and a smaller front (outside) bearing being positioned from about ½ inches to about 2 inches apart depending upon the housing geometry. In the preferred embodiment, the bearing races of the inside and outside bearings are spaced about ½ inches apart. 
         [0024]    The housing has a cylindrical cavity (bore) which forms a central tubular-like portion shaped as the result of the boring through the alloy block. This tubular-like portion holds the bearings that in turn support the shaft which passes through it. Surrounding, and laterally extending outwardly from the central tubular-like portion of the housing are projecting ears having through holes for mounting studs and also a build-out wall carrying threaded holes for receiving bolts. These structures are used to mount the housing to the differential with the same mounting components used for mounting the removed O.E.M. transmission. 
         [0025]    A front boss, which extends forward from the front (outside) face of the housing block, receives the outside (front) bearing race and its bearing and permits the overall weight of the housing structure to be reduced by permitting a reduction in the thickness of the projecting ears and the thickness of the wall build-out mounting structures. In addition, the boss has a thinner wall than the body of the housing, which permits more heat to dissipate from the front (outside) bearing region, thereby permitting the use of a smaller front bearing, than with the rear bearing which is positioned within the main body of the housing. 
         [0026]    The rear bearing race and its rear bearing are inserted into the rear portion of the bore which is concentric with the center of the toroidal-shaped flange. 
         [0027]    The bore has two internal annular shoulders with different through bore diameters which are stepped from one to the other, with the inner (rear) shoulder having the smaller (bore diameter) opening and the outer (front) shoulder having the larger (bore diameter) opening. The inner shoulder operates as the abutment stop for both the front and rear bearing races. The longitudinal thickness of this shoulder establishes the spacing between the outside and inside bearings. 
         [0028]    The portion of the bore leading from the rear (inside) face of the housing to the inner (rear) shoulder is a neat (tight) fit for the circumference of the rear (inside) bearing race. Similarly, the inside bore diameter of the outer (front) shoulder is a tight fit for the circumference of the outside (front) bearing race. The bore portion leading from the front (outside) face of the housing to the outer (front) shoulder is about the same size in bore diameter as that leading from the rear (inside) face to the rear (inside) shoulder. This outside (front) bore portion has an annular oil grove in its inside wall positioned away from the front (outside) shoulder. 
         [0029]    A pair of grease ports lead from two separate side faces of the housing to the inside face of the rear (inside) annular shoulder. Each grease port is tapped and threaded to receive a fitting. The first port is positioned on a side face of the housing significantly lower than the second port, which is positioned on the top side face of the housing. The lower first port is fitted with a snap-fit grease fitting for feeding grease to the interior of the housing at the inside (rear) annular shoulder. The upper second port is fitted with a pressure relief/bleeder fitting. 
         [0030]    As the bearings are open bearings, grease forced into the housing will first fill the bearings and then fill the bore about the shaft in both the front (outside) and rear (inside) bore portions. These grease pockets provide additional sources of lubrication for the bearings. A rear (inside) grease/oil seal having an internally mounted double layer wiper seal is mounted at the back (inside) bore portion housing wall. 
         [0031]    A front (outside) grease/oil seal is mounted at the front (outside) bore portion housing wall. A coupling yoke mounted to the front of the shaft carries a dust cover for the front (outside) grease/oil seal. 
         [0032]    The shaft has a spline section at both of its ends. The rear (inside) spline mates with a gear in the differential. The front (outside) spline is used to mount the coupling yoke. 
         [0033]    Inboard from the front (outside end) shaft spline is a section of the shaft which is machined to receive the rear (inside) bearing and then the front (outside) bearing, both in press-fit fashion. This machined section terminates at a peripherally/outwardly extending circular flange machined with a flat face adjacent the machined shaft surface and with a fillet on the opposite side. 
         [0034]    The shaft has a threaded end outboard of its yoke-mounting spline section. This treaded end receives a nut which tightens against the hub of the yoke to draw the assembly together. 
         [0035]    The yoke has a Y-shaped coupling end of cast material. A central longitudinal bore has been cut though the hub of the coupling with an internal spline. The side opposite the Y-shaped coupling has a projecting boss or cylindrical projection for abutting the back of the front (outside) bearing. The opposite end of the hub has a machined face against which a tightening nut operates when engaging the threads at the shaft end. 
         [0036]    The outer (front face) of the housing has a series of threaded holes above and below the housing boss. These holes are for mounting a bracket, which can be mounted above or below the housing boss, depending upon the geometry of the assembly. The bracket has a pair of tabs or ears for mounting it to a pair of frame mounts. 
         [0037]    The adaptor is assembled by first pressing the front (outside) and rear (inside) bearing races into the bore to abut the inner (rear) annular shoulder, which has the grease openings on its inside face. The rear (inside) bearing is pressed over the machined section of the shaft to abut the machined face of the flange. 
         [0038]    The shaft is extended through the housing, and the front bearing is started onto the machined section of the shaft. A crushable separator may be used to separate the bushings until the shaft assembly is tightened. The front seal is tapped into place at the front bore opening. Then the coupling&#39;s spline section is started onto the mating spline section on the shaft. The nut is then started on the threaded end of the shaft. Tightening the nut forces the two bearings into the housing bores. When the bearings are sufficiently “set”, i.e., the assembly is sufficiently tight. Then the rear (inside) grease seal is assembled over the outside edge of the flange and the rear (inside) dust cover is tapped tight against the rear (inside) bore opening. The housing is then greased to completely fill all spaces with grease. Then bearing play is checked and the nut is finally tightened to set the bearing tightness for operation. 
         [0039]    The housing is mounted to the differential at the five mounting points of the removed O.E.M. transmission. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0040]    The features, advantages and operation of the present invention will become readily apparent and further understood from a reading of the following detailed description with the accompanying drawings, in which like numerals refer to like elements, and in which: 
           [0041]      FIG. 1  is a partial perspective view of the adaptor of the present invention mounted to the rear differential of a C5 generation rear suspension which is mounted to the frame of an earlier generation Corvette; 
           [0042]      FIG. 2  is a second partial perspective view of the adaptor of  FIG. 1  with the drive shaft connected to the coupling of the adaptor; 
           [0043]      FIG. 3  is a perspective view of the adaptor mounted to the rear differential with the mounting bracket above the shaft for holding mounting bushings; 
           [0044]      FIG. 4  is a front perspective view of the assembled adaptor for the set up of  FIG. 3  before being mounted; 
           [0045]      FIG. 5  is an opposite side perspective view of the assembled adaptor with a bracket; 
           [0046]      FIG. 6  is a rear perspective view of the assembled adaptor with a lower mounted bracket; 
           [0047]      FIG. 7  is an exploded assembly view of the adaptor from a front perspective view; 
           [0048]      FIG. 8  is a side cross-sectional view of the adaptor taken as shown in  FIG. 5 ; 
           [0049]      FIGS. 9   a  and  9   b  are front and front-perspective views of the housing portion of the adaptor, respectively; 
           [0050]      FIGS. 10   a  and  10   b  are rear and rear-perspective views of the housing, respectively; 
           [0051]      FIG. 11  is a bottom view of the housing with the rear seal ring installed on the periphery of the rear flange; 
           [0052]      FIG. 12  is a front-perspective view of the bracket; 
           [0053]      FIG. 13  is a side view of the stub shaft; and 
           [0054]      FIG. 14  is a front view of the drive shaft coupling yoke. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0055]    The present invention is an adaptor  21 ,  FIG. 1 , for mating the front mounted engine and transmission of an older generation Corvette to a newer generation, specifically a C5 or C6 rear differential and suspension. The adaptor  21 ,  FIG. 1 , bolts to the front of a C5 or C6 differential  23  in place of the removed O.E.M. transmission. The adaptor  21  includes a housing  25 ,  FIGS. 1-2 . A bracket  27  is bolted to the front face  29  of the housing  25 . This bracket  27  also bolts to frame mounts  31 . This bracket  27  can be bolted below a shaft  33  (not shown in  FIG. 1 ) and coupling yoke  35  as shown in  FIG. 1 , or above them, depending upon the geometry of the vehicle frame  37  and the mounting configuration of the rear suspension assembly of which the differential  23  is a part. 
         [0056]    The adaptor  21  assembly,  FIGS. 2-8 , and in particular, the housing  25  carries a pair of threaded holes  39  (not shown in  FIG. 2 ) near the top of its rear/inside face  41  and another near the bottom (not shown in  FIG. 2 ) for mounting the housing  25  with the differential  23 , with mounting bolts  43 . Internal to the housing  25  is a stub shaft  33  (not shown in  FIGS. 1-3 ). In addition, mounted on the front/outside end of the stub shaft  33  is the coupling yoke  35  to which the vehicle drive shaft  45  is connected,  FIG. 2 . The housing  25  is machined from a block of alloy material. 
         [0057]    The housing  25 ,  FIGS. 3-4 , has a series of four threaded holes  47  near the top of its outer face  29  extending in an arc above a front boss  49 , which boss projects forward from the outer/front face  29  of the housing  25 . A second series of similar sized and spaced threaded holes  47  are below the front boss  49  in a similar arc. 
         [0058]    The threaded holes  47  are used to mount a bracket  27  to the front/outer face  29  of the housing  25 , either above or below the boss  49  with fastening bolts  51 . The bracket  27  connects to frame mounts  31  above the differential,  FIG. 3 , or below the differential,  FIG. 5 , depending upon the geometry of the frame-to-rear suspension setup.  FIG. 4  shows the bracket  25  attached in the upper position, while in  FIGS. 5-6  the bracket  25  is in the lower position. 
         [0059]    The assembled adaptor  21  as shown in  FIGS. 4-6  has a stub shaft  33  which passes completely through the housing  25 . The rear/inside end of the shaft  33  is splined with a rear spline  53  extending to the rear/inside end of the shaft  33 . The opposite end of the shaft  33  has the coupling yoke  35  mounted thereto and held on with an end nut  55 ,  FIG. 3 . The rear/inside face  41  of the housing  25  carries a toroidal-shaped flange  57  through which the stub shaft  33  extends. This flange  57  and other housing features are discussed further below. 
         [0060]      FIG. 7  is an exploded assembly view of the adaptor  21  shown from a side view.  FIG. 8  is a side cross-sectional view of the assembled adaptor  21  taken as shown in  FIG. 5 . 
         [0061]    The housing  25  has a central bore  59  machined through it from its rear/inside face  41  to its front/outside face  29 . The shaft  33  extends through the bore  59  and is supported by a front bearing  61  and a rear bearing  63 . Each of these bearings is a thrust bearing with cylindrical rollers. There are mating front  65  and rear  67  bearing races, respectively. A front grease seal  69  and a rear grease seal  71 , seal the respective ends of the shaft and bearings. A tubular spacer is positioned between the bearings  61 ,  63 . This spacer is crushable when the assembly is tightened. 
         [0062]    The housing through bore  59  includes a pair of interior annular flanges which will be discussed further below. The backs of the bearing races  65 ,  67  abut one of these flanges to establish the position of the bearings  61 ,  633  within the housing  25 . 
         [0063]    The bearings and bearing races are supplied by The Timken Company. The product numbers for these bearings  61 ,  63  and races  65 ,  67  are product numbers M88010, M88048 HM89444, and HM89410, respectively. The grease seals are supplied by SKF USA. The product numbers for these seals  69 ,  71  are CRW1 R and HMSA25P, respectively. 
         [0064]    The housing  25 , itself, is shown in  FIGS. 9   a ,  9   b ,  10   a ,  10   b  and  11 , and has an irregular shape. Its overall outline is hexagonal with a smaller ear  77  on one bottom side and a larger ear  79  on the other bottom side. It is machined from high-strength aluminum alloy with a center bore  59  of about 2 inches in diameter in its smallest section. The size of the housing is about 3⅜ inches from the front face of the front boss  49  to the rear face of the toroidal flange  57 . The overall height of the housing is about 6½ inches, and the overall width is about 9⅜ inches. 
         [0065]    The toroidal flange  57  is about 6 inches in diameter with a 3-inch diameter bore opening  59  at its rear face. This flange  57  is about ⅜ inches thick, i.e., it extends about ⅜ inch outward from the rear face  41  of the housing  25 . A 1/16 inch deep groove  73  extends about the peripheral wall of the flange  57  and holds an O-ring seal  75 . When the housing is mounted onto the rear differential of the vehicle, the seal  75  seals the opening of the differential  23  to prevent grease from leaking out. 
         [0066]    The threaded bolt holes  39 , previously not shown on  FIG. 2 , are easily seen on the rear face  41  of the housing  25 ,  FIG. 10   a , and are each about ½ inch away from the edge of the toroidal flange  57 . These holes  39  each receive 5/16 inch fastening bolts  51  in the mounting positions for the vehicle&#39;s differential. 
         [0067]    The 3-inch diameter bore  59  extends into the housing a distance of about 1½ inches to terminate in a first internal annular shoulder  81  having an inside (bore) diameter of about 2⅛ inches in diameter,  FIG. 10   a.    
         [0068]    Each of the smaller and larger ears  77 ,  79  is shaped to provide a fastening point having a drilled hole  83 ,  85  therethrough. These holes are each ⅜ inches in diameter and have about a ⅝ inch deep, ⅝ inch diameter counter  87  sink on the front/outside housing face  29  side of each ear  77 ,  79 . 
         [0069]    The two sets of four threaded holes  47  for holding the bracket  27 , are spaced in a circular arc of about 120 degrees, on a 3-inch bolt radius, with one set of holes  47  above and other set below the front boss  49 ,  FIGS. 9   a ,  9   b . Each of these bracket mounting holes is tapped to receive a ⅚ inch bolt. The arc center of these holes is about 1 inch away from the outside wall of the front boss  49 . 
         [0070]    Front boss  49  has about a 4-inch outer diameter and a 3-inch inner diameter which extends inward about ¾ inches to terminate in a second internal annular shoulder  89 ,  FIGS. 9   a ,  9   b . This shoulder  89  is about 3/16 inch high, i.e., it extends inwardly to establish its internal bore at about 2⅝ inches in diameter. 
         [0071]    The second shoulder  89  is about ¾ inches deep (wide) and terminates against the first internal annular shoulder  81 . The first internal shoulder  81  is about ½ inches wide and joins the second shoulder  89  to the 3-inch bore  91  extending from the outer face of the toroidal flange  57 . 
         [0072]    A first grease passageway  93  extends from a side face  95  of the housing  25  to the inside face of the first internal annular shoulder  81 . This first grease passageway is fitted with a NPT Zerk-type grease fitting  97 . 
         [0073]    A second grease passageway  99  extends from the top face of the housing  25  to the inside face of the first internal annular shoulder  81 . This second grease passageway is fitted with a plug  103  which can have a pressure-indicating, air-release, spring biased pin. 
         [0074]    The bracket  27 ,  FIG. 12 , has a mounting wall  105  with an arc-shaped cutout section  107  to provide clearance for the front boss  49 . Four holes  107  are drilled through the mounting wall  105  about the arc-shaped cutout to line up with either of the upper or lower four threaded holes  47  on the housing front/outside face  29 . A pair of frame-mount receiving ears  111  extend perpendicularly outward from the mounting wall  105  at either end of the bracket  27 . Each ear  111  has a ½ inch drilled hole for receiving and holding a frame mount  31 . The bracket is about 12 inches long, with the ears each being about 2½ inches long by 2 inches wide. The bracket mounting wall  105  and the ears  111  are of ¼ inch thick, tempered, high carbon steel plate. 
         [0075]    The shaft  33 .  FIG. 13  is about 15 inches long, end-to-end. The rear portion  113  of the shaft has been machined to have about a 1 inch outside diameter, and is about 8¾ inches in length from the rear of the spline  53  to a fillet  115  side of a circular flange  117 . The rear spline portion  52  is about 2 inches long. 
         [0076]    The circular flange  117  is about ¼ inch wide and 2 inches in diameter. The opposite side  119  of the circular flange  117  is machined flat to abut the rear bearing  63 . Forward of the machined flat side  119  of the flange is a machined and polished section  121  of the shaft  33 , which receives and holds both bearings  61 ,  63  and bearing races  65 ,  67 . This polished section  121  is about 2⅜ inches long and has about a 1¼ inch outside diameter. Forward of the polished section  121  the shaft is necked down to about 1 inch in outside diameter leading to a front spline  123 . This front spline section  123  is about 1⅜ inches long. Outboard/forward of the front spine  123  the shaft  33  is machined and threaded into a 1 inch long, 11/16 inch diameter threaded bolt portion  125  for receiving the end nut  55 . 
         [0077]    The drive shaft coupling yolk  35  is shown in greater detail in  FIGS. 7 and 14 . This coupling  35  includes a pair of U-bolts (not shown) for engaging the arms of the yolk. The coupling  35  is provided by Greg Moser Engineering, Inc. product number PY210-9. It is a 1310 series pinion yoke having U-joint with 28 internal splines  135 ; and it is made of forged steel. The coupling U-joint portion  127  is about 3 inches deep with arms  129  about 2⅛ inches apart. A stub cylinder  131  extends from the opposite end of the coupling  35  from the U-joint  127 . This cylinder  131  is machined to be about ⅞ inch long, with an outside diameter of about 1⅞ inches. A dust shield  133  for the front grease seal  69  is peened into place on the cylinder  131  at a location where the U-joint  127  and the cylinder  131  meet. 
         [0078]    The internal  28  spline section  135  extends thorough the coupling  35  from the base of the U-joint portion  127  to about 11/16 inch from the outside end of the cylinder  131 . 
         [0079]    The two arms  129  of the U-joint portion  127  of the coupling are bifurcated into two pads  137  both of which are drilled to receive an end of a U-bolt. Each U-bolt is forged to be about 1⅞ inches long, and to receive and hold a transverse bar of about 1 inch in outside diameter, with the ends of each U-bolt being threaded for 5/16 inch lock nuts (not shown). 
         [0080]    Many changes can be made in the above-described invention without departing from the intent and scope thereof. It is therefore intended that the above description be read in the illustrative sense and not in the limiting sense. Substitutions and changes can be made while still being within the scope and intent of the invention and of the appended claims.