Vehicles made by American Motors Corporation (AMC) and Jeep incorporated a variety of transmissions and transfer case systems. This article covers transmissions used in the following vehicle models and years: All American Motors (AMC) passenger cars, 1954-1988 Jeep Cherokee XJ (1984–2001) Jeep Comanche (1986-1992) Jeep CJ (1976–1986) Jeep Grand Cherokee WJ (1999–2004) Jeep Grand Cherokee ZJ (1993–1998) Jeep Wagoneer/Grand Wagoneer (1963–1993) Jeep Wrangler YJ (1987–1995)
Transmissions
Transmissions are a mechanical component of a vehicle that transfers power from the engine to the wheels. They allow the engine to operate within a set range of speeds. Various gear ratios are used to multiply the engine torque when a greater pull force is needed (like when a car starts from a stopped position, or is driving up a hill), or to reduce the engine speed at higher vehicle speeds. There are two types of transmissions: manual and automatic. Manual transmission require the driver to select specific gears, while automatic transmissions select the gears by themselves. AMC and Jeep vehicles have used a mix of manual and automatic transmissions in their car models over the years, largely due to specific vehicle, engine, model year, and drivetrain configuration.
In the four-wheel drive AMC and Jeep vehicles, the transmission is usually connected to a transfer case, which distributes the engine power to the vehicle's drive axles. The design of the transmission directly affects the compatibility with other drivetrain components. For instance, in the later AMC transmissions, 21-spline or 23-spline output shafts were used which corresponded to compatible transfer-case inputs. Other factors like gear ratios, bell housing patterns, or output-shaft dimensions also vary across transmissions and affect which engines and transfer cases can be used in junction.
Manual
The following manual transmissions have been used in the vehicles listed above: Aisin AX4 four-speed (used with 4 cyl and 2.8 L V6) Aisin AX5 five-speed (used with 4 cyl and 2.8 L V6) Aisin AX15 five-speed (used with 4.0 L from 1989) Borg-Warner HR1 four-speed synchronized unit (used only with the 121-4 engine) Borg-Warner SR4 four-speed synchronized unit (late-1970s/early-1980s 6 cylinder and 304 V8) Borg-Warner T4 four-speed (used only after 1981) Borg-Warner T5 five-speed (used only after 1981) Borg-Warner T10 four-speed (car only) Borg-Warner T14 three-speed Borg-Warner T15 three-speed Borg-Warner T18 four-speed (4:1 first gear) Borg-Warner T18A four-speed (6:1 first gear) Borg-Warner T85 three-speed Borg-Warner T86 three-speed Borg-Warner T89 three-speed Borg-Warner T96 three-speed Borg-Warner T90 three-speed Borg-Warner T98 four-speed Peugeot BA-10/5 five-speed Tremec T176 four-speed (used with AMC 6-cylinder, ISUZU 4L Diesel and 304 V8 engines) Tremec T177 four-speed (used only from 1980 to 1988 in full size Jeeps with V8) Tremec T150 three-speed (also called 150T)
Automatic
The following automatic transmissions have been used in the vehicles listed above: Borg-Warner M8, M10, M11A, M11B and M12; cast-iron three-speed automatic with torque converter; used in many AMC 6- and V8-cylinder passenger cars built between 1957 and 1971. These transmissions were either air-cooled with fins on the torque converter and ducts in the bell housing adapter (six cylinder applications) or liquid-cooled, and were marketed under the name "Flash-O-Matic." Borg-Warner M35, M36, and M37. Three-speed gear set with torque converter, air-cooled. Used in the Rambler American 6-cylinder cars between 1963 and 1969 as "Flash-O-Matic." Borg-Warner M40, M42, M43, and M44. 3-speed with torque converter, water-cooled. Used in AMC 6- and V8 engines between 1970 and 1971; also the 290 2-bbl V8 engine between 1967 and 1969 (M40). Marketed as "Shift-Command." Aisin-Warner AW4 four-speed; from 1987 in XJ and MJ with 4.0 L and some 2.5 L. GM THM400 three-speed with AMC pattern from 1974 to 1979 and Buick Nailhead case with adapter rings to fit AMC 327, Buick 350 and V6 as well as AMC V8 before 1974 Chrysler 45RFE four-speed Chrysler 545RFE five-speed (used with 5.7 L Hemi engine and VM Motori 2.8 L Turbo Diesel, same as 45RFE used with 4.7 L, but different software enabling a second overdrive) TorqueFlite 998 three-speed; used with the 4.2 L I6 in most AMC cars and 304 V8s. TorqueFlite 904 or 909 (lockup) three-speed; used with the 2.5 L I4 or 3.8/4.2 L I6 in most AMC cars from 1972 to 1983, and also from 1980 to 1987 Jeeps, as well as with the 2.0 L Audi engine in Postal Jeeps TorqueFlite A727 three-speed; used in AMC Jeep applications with V8 and some I6 engines (can be swapped into Eagles, etc., for 998 replacement) TorqueFlite A727 with Mopar big block pattern and adapter to Nissan SD33 diesel (CJ10A tugs mostly. Shared with IH Scouts) TorqueFlite 30RH three-speed; 1984-96 2.5 L XJ Cherokee TorqueFlite 32RH three-speed; 1994 4.0 L XJ Cherokee (limited use export only) TorqueFlite 32 RH three-speed; 19974.0 L TJ Wrangler TorqueFlite 42RE four-speed; 1994-96 4.0 L Grand Cherokee, 1996 V8 Grand Cherokee TorqueFlite 44RH four-speed; 1994 Grand Cherokee (limited use) TorqueFlite 44RE four-speed; 1996 Grand Cherokee TorqueFlite 46RH four-speed; 1993-95 5.2 L Grand Cherokee TorqueFlite 46RE four-speed Ultradrive 42RLE four-speed
Aisin-Warner The Aisin-Warner four-speed automatic transmission (AW4) was co-designed by AMC and Borg Warner, and built by Aisin in their new facility for use with the Cherokee XJ's 4.0L inline six cylinder engine. It was manufactured by Aisin-Warner, a member of the Toyota group, in partnership with Borg-Warner. It shares many parts with the Aisin 450-43LE that is used in Toyota off-road vehicles.
The AW4 is also used behind the 2.5 L (150 CID) AMC Straight-4 engine. It has a removable bell housing with a mount for the crankshaft position sensor. Early AW4s used 21-spline output shafts. In 1991 the AW4 was changed to a 23-spline output shaft, concurrent with adoption of the High Output (commonly known as H.O.) inline six-cylinder engine. Some sources state that the output shaft spline change occurred for the 1990 model year. The change most likely occurred during the 1990 model run with early 1990 models receiving 21-spline transmission and later models receiving 23-spline. If swapping transmissions in 1990 model year vehicles either swap the transfer case as well or make sure to check spline count. The input on the transfer case can also be changed to match the output shaft spline count. Rear-wheel-drive-only transmissions all have the same spline count on the output shaft, only 4x4 models are affected by differing spline count.
Gear Ratios for the AW4: 1st: 2.80 2nd: 1.53 3rd: 1.00 4th: 0.75 (23-spline, 0.705 21-spline)
Models that used the AW4: 1987–2001 Jeep Cherokee (XJ) 4.0 L 1993–1993.5 Jeep Grand Cherokee (ZJ) 4.0 L 1987–1992 Jeep Comanche 2.5 L 1987–1992 Jeep Comanche 4.0 L
Chrysler/TorqueCommand
For the 1972 model year, American Motors Corporation (AMC) made a significant shift in its automatic transmission strategy, discontinuing its long-standing use of BorgWarner units and beginning the purchase of variations of the robust Chrysler-developed TorqueFlite transmission. AMC branded these transmissions as TorqueCommand. Starting with the 1980 model year, the Chrysler automatic replaced GM's Hydramatic automatic transmissions in Jeep vehicles.
All TorqueCommand automatic transmissions have a 23-spline output shaft. A characteristic of these transmissions is a high degree of internal commonality with Chrysler's TorqueFlite units. Beyond the bell housing pattern (integral to the main transmission case) and the torque converter, the AMC versions are identical to their Chrysler counterparts, with most internal components interchangeable.
However, a crucial distinction lay in the torque converter and flexplate design. Unlike Chrysler torque converters, which typically featured a pressed-on ring gear for the starter teeth, AMC's TorqueCommand transmissions have a traditional 164-tooth flexplate similar to Ford's. This means that torque converters are not interchangeable between AMC and Chrysler applications, despite the internal similarities of the transmission units.
As AMC evolved its engine lineup, including introducing lighter casting technologies for its mainstay engines, the TorqueCommand transmissions were adapted with various bell housing patterns to accommodate different applications. This flexibility allowed AMC to integrate the transmissions across a wide range of vehicles and engines, both in-house and outsourced:
AMC I6 and V8 engines (late model pattern) - The primary application for the TorqueCommand was with AMC's I6 and V8 engines. These transmissions featured a specific "AMC late model pattern" bell housing. This pattern was used with 232, 258, and 4.0 L I6s, as well as the 304, 360, and 401 V8s.
AMC 150 (2.5L) I4 (Chevrolet small V6 pattern) - This four-cylinder application adopted the General Motors small V6 engine bolt pattern. This decision was strategic, as the new AMC 2.5 L engine replaced the I4 engines AMC purchased from GM. Furthermore, AMC continued to source the 2.8 L V6 from GM until the introduction of the AMC 4.0 L I6 in 1987, and both the 2.5 L I4 and GM's V6 shared common drivetrain components in Jeep vehicles. This pattern was used in 1980 and later CJs, and from 1980 to early 1983 AMC Eagles equipped with the I4 engine. The 2.5 L engine maintained this GM 60-degree V6 pattern through the end of its production, a pattern also shared with some front-wheel-drive Cadillac engines.
Audi 2.0 L I4 (a limited pattern) - From 1979 through 1981, AMC also utilized a 904 TorqueCommand variant with an Audi 2.0 L engine.
Transfer cases
The transfer case is an auxiliary transmission that connects the front and rear axles. It also commonly provides a selectable secondary gear reduction. AMC and Jeep vehicles have used several different transfer cases in their various models.
Case Offset Spline Ratio Bolt Pattern Years Used Borg-Warner 13-39 Both left 10 2.57:1 THM400 1973–1979 Dana 18 Both left 6 (10) 1.98:1, 2.42:1, 2.46:1 Texas 1940–1971 Dana 20 Front left 6 (10) 2.03:1 Texas 1963–1979 Dana 300 Front left 23 2.62:1 Round (New Process) 1980–1986
Dana Jeep has used three different transfer cases made by the Spicer Division of Dana Holding Corporation. They are the 18, 20, and 300 models.
Dana 18 The Dana 18 is a gear driven part-time transfer case. Both the front and rear output shafts are offset towards the passenger side of the vehicle. Drive modes offered include 2-wheel high, part-time 4-wheel high, and part-time 4-wheel Low. All Dana 18 cases are cast iron and use the "Texas" bolt pattern with five bolts holding on the transfer case. There are five variations:
27-tooth drive gear, 3/4" intermediate shaft and 1.98:1 low range, input hole 26-tooth input gear, 3/4" intermediate shaft and 2.42:1 low range, input hole 26-tooth input gear, intermediate shaft and 2.42:1 low range, input hole 26-tooth input gear, intermediate shaft and 2.42:1 low range, input hole 29-tooth input gear, intermediate shaft and 2.46:1 low range, input hole, Dana 20 case
The normal (3") input Dana 18s are interchangeable, but the input gear must match the transfer case. The "big hole" (4" input) Dana 18 is transmission-interchangeable with the Dana 20. Almost all Dana 18 and Dana 20 input gears are 6-spline; the only exception is the one used with the 10-spline version of the T14 transmission. Some International Scout Dana 20s with a 727 automatic transmission use a 23 spline 26 tooth gear