AMC and Jeep transmissions
Encyclopedia
Vehicles made by American Motors Corporation (AMC) and Jeep
have used a variety of transmission
s and transfer case
systems throughout the years in which they have been produced. This article covers transmissions used in the following vehicle models and years:
used in later AMC vehicles came with either a 21-spline
or a 23-spline output shaft. Transmissions coupled to four-cylinder engines normally used 21-spline output shafts. The 23-spline manual transmission
was universal in the Eagle
lines and was generally used with six-cylinder applications. All transfer cases were available with inputs matching either 21- or 23-spline shafts, so transmission swaps are possible among various models and years.
new inline six-cylinder 4.0 L design. 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 in³) 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:
Models that used the AW4:
transmission and called it the TorqueCommand. All TorqueCommand automatics used 23-spline output shafts. These transmissions were available in both the Chevrolet V6 pattern (used on the AMC 150 I4 and Iron Duke
I4 engines) and the AMC late model pattern that was used on their I6 and V8 engines.
transmission that was used by Jeep, evolved from the original A604/A606 Ultradrive. Per its model designation it contains four gears and a torque
rating of two. The 42RLE is a modified 42LE where as it is designed to mount longitudinally for rear wheel drive instead of transversely for front wheel drive. By design it has full electronic shift control with adaptive memory to learn the operator's driving habits controlled by the vehicle's Transmission Control Module (TCM). Contained within the automatic's torque converter is an Electronically Modulated Converter Clutch(EMCC) designed act as a shock absorber for harsh shifting.
Gear Ratios for the 42RLE:
Models that used the 42RLE
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.
Summary of AMC/Jeep Transfer Cases
See below for further information on New Process/New Venture transfer cases.
reduction unit that bolts to the back of the transfer case. This assembly as a unit was designated as the BW 13-39.
The BW 13-39, which is often, but not always, imprinted with the casting number 13-39, was the first Jeep transfer case to be made of aluminum and to be chain-driven. The output for both the front drive shaft and the rear drive shaft is on the right side. This unique transfer case had an integrated limited-slip differential that splits power between the front and rear drive shafts. It used a vacuum
-operated differential that was available for use in both high and low range. A vacuum switch (usually located in the glove compartment
) allowed the differential to be controlled by the driver.
The BW 13-39 was used only with AMC's version of the THM400 automatic transmission, which had a special extra-long 10-spline output shaft, between 1973 and 1979. It is not bolt-compatible with any other Jeep transmission.
rear output. 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:
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.
All Dana 18s have front and rear outputs offset to the right side. Most vehicles built with a Dana 18 have the rear axle offset to the right side to accommodate this. Most other transfer cases used in Jeeps have a centered rear output that lines up with the input shaft. The Dana 18 always has gears turning, which makes it noisier then some other transfer cases when in two wheel drive mode.
construction, and deep oil pan. Like the Dana 18, it uses the Texas bolt pattern to hold the transfer case in place. This is a heavy-duty, gear-driven transfer case with a 26-tooth input gear. The output for the front drive shaft is on the right side and the rear output is in line with the input. Its low range has a ratio of 2.03:1.
The Dana 20 is generally compatible with the "big hole" Dana 18. One exception is the version used with the THM400 in full-size Jeep trucks, which used a different spline number on the input gear.
One common modification of the Dana 300 is to add oil paddles to the main shaft to prevent oil starvation of the rear bearing.
The Dana 300 was used in Jeep CJs from 1980 to 1986. The 1980 factory original came with a shorter tail housing and a longer rear drive shaft. The Dana 300 should fit behind all TorqueCommand 4x4 transmissions.
ranges
. The second digit is a series number that reflects design, and provides minimal information about torque handling. For example, if the second digit is a 1, there is no two wheel drive option; if it is a 2, 2WD is available. Other numbers have similar meanings. The third digit indicates differential type: 1 means locked (no differential), 2 means open, 3 means electric locked, 4 and 5 both indicate an asymmetrical torque
split planetary
gear and gear drive, 6 means an electronic clutch pack, 7 means a hydraulic clutch pack (except for the unique 207), and 9 means a viscous coupler.
The AMC Eagle used three New Process transfer cases (Models 119, 128, and 129) that were single speed versions of the models (219, 228, and 229) that were used in 1980 and newer Jeeps. There was no difference between the Eagle versions and the Jeep versions other than the addition of a low range, indicated by the 2 as the first digit.
New Process transfer cases are chain-driven and use a circular 6 bolt, 23-spline input on the case. The output for the front drive shaft is on the left side. The New Process transfer cases used by AMC attach the same as the Dana 300 except that New Process cases have the front output on the left side. Interchange ('flip') is possible, but there is an indexing lug in the pattern, in an attempt to allow the transfer case to attach in only one position. Thus, some modification on the transfer case or the adapter is required.
Because of changes in the name of the manufacturing company, new versions of the NP231 and NP242 are referred to as NV (New Venture) or NVG (New Venture Gear).
New Process Transfer Cases Used in AMC/Jeep Vehicles
↑ The 249 was available in two versions. The early (1993–1996) version had no differential lock and the viscous coupling spanned the center differential, creating a 50/50 torque split. The later version (1996 and beyond) had a viscous front drive, creating a rear torque bias, but included a provision to lock the center differential.
The Dana 18 has a Power take-off
(PTO) attachment on the case that can be used to drive equipment that accepts PTO input. A unique feature of the Dana 18 is the overdrive that attaches in the PTO port in the back of the system. An adapter allows use of both the overdrive and the PTO attachment, but it is no longer produced.
Laycock-DeNormanville overdrive was available from 1974 through 1976 for inline six with the 150T and V8 torque tube cars with the T89.
Clocking refers to the angle at which the transfer case is tilted with reference to the horizontal plane. Stock Jeep clocking for the Dana 300 (1980–1986) is usually 23° and stock Eagle and Jeep/New Process clocking is usually 13°. Many factors, most notably ground clearance and front drive shaft clearance, can necessitate a change in the clocking angle. Some aftermarket adapters, such as those manufactured by Novak Conversions feature flanges with multiple clocking options.
bolt pattern for the old AMC 196 Straight-6 engine is the same as for the more modern 199 and 232 (used in 1964–1971), but the 196 had different dowel pin sizes. When AMC dropped the GEN-1 V8 engines in 1966, the bell housing changed, but all later V8 bell housings are the same. The bell housing for six cylinder engines changed to match the V8 in 1972 when AMC switched from Borg-Warner to Chrysler transmissions. The flywheel also changed from 153 teeth (a common Chevy size) to 164 teeth (a common Ford size).
The Iron Duke I4 transmission bolt pattern varies between the Chevrolet Small Six and the BOP (Buick, Oldsmobile, Pontiac). The later AMC I4 had a Small Six bolt pattern, and this was retained for the life of the engine. AMC often used lighter duty transmissions with these engines.
Companies
Parts
Jeep
Jeep is an automobile marque of Chrysler . The first Willys Jeeps were produced in 1941 with the first civilian models in 1945, making it the oldest off-road vehicle and sport utility vehicle brand. It inspired a number of other light utility vehicles, such as the Land Rover which is the second...
have used a variety of transmission
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
s and transfer case
Transfer case
A transfer case is a part of a four-wheel-drive system found in four-wheel-drive and all-wheel-drive vehicles. The transfer case is connected to the transmission and also to the front and rear axles by means of drive shafts...
systems throughout the years in which they have been produced. This article covers transmissions used in the following vehicle models and years:
- AMC ConcordAMC ConcordThe AMC Concord is a compact car produced by the American Motors Corporation for the 1978 through 1983 model years. The Concord replaced the AMC Hornet and to some extent the mid-size AMC Matador, discontinued after 1978 in a market moving to downsized automobiles...
(1978–1983) - AMC EagleAMC EagleThe AMC Eagle is a compact-sized four-wheel drive passenger vehicle that was produced by American Motors Corporation . The AMC Eagle line of vehicles inaugurated a new product category of "sport-utility" or crossover SUV....
(1980–1988) (Note: This is not the same as the Chrysler EagleEagle (automobile)Eagle was a marque of the Chrysler Corporation following the purchase of American Motors Corporation and aimed at the enthusiast driver.Though short-lived, the Eagle Vision sedan sold in respectable numbers, while the sporty Eagle Talon sold more than 115,000 units.-Overview:Following the...
) - AMC PacerAMC PacerThe AMC Pacer is a two-door compact automobile produced in the United States by the American Motors Corporation between 1975 and 1980.Its initial design idea was started in 1971. The car's unusual rounded shape with massive glass area greatly contrasted with the three-box architecture with "square,...
- AMC SpiritAMC SpiritThe AMC Spirit was a subcompact marketed by American Motors Corporation from 1979 to 1983 as a restyled replacement for the Gremlin. The Spirit shared the Gremlin's platform and was offered in two hatchback variations, each with two doors — marketed as sedan and liftback...
(1979–1983) - Jeep Cherokee XJJeep Cherokee (XJ)The Jeep Cherokee is a unibody compact SUV. It shared the name of the original full-size SJ model, but without a body-on-frame chassis, it set the stage for the modern SUV. Its innovative appearance and sales popularity spawned important imitators as other automakers began to notice that this...
(1984–2001) - Jeep CJJeep CJThe Willys CJ is a public version of the famous Willys Military Jeep from World War II.The first CJ prototype was introduced in 1944 by Willys, and the same basic vehicle stayed in production through seven variants and three corporate parents until 1986.A variant of the CJ is still in production...
(1976–1986) - Jeep Grand Cherokee WJ (1999–2004)
- Jeep Grand Cherokee ZJ (1993–1998)
- Jeep WagoneerJeep WagoneerThe Jeep Wagoneer was an early sport utility vehicle and the first luxury 4x4, produced under varying marques from 1963 to 1991. It was noteworthy for being in production for more than 28 years with only minor mechanical changes...
/Grand Wagoneer (1963–1991) - Jeep Wrangler YJ (1987–1995)
Transmissions
TransmissionsTransmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
used in later AMC vehicles came with either a 21-spline
Rotating spline
Splines are ridges or teethon a drive shaft that mesh with grooves in a mating piece and transfer torque to it, maintaining the angular correspondence between them....
or a 23-spline output shaft. Transmissions coupled to four-cylinder engines normally used 21-spline output shafts. The 23-spline manual transmission
Manual transmission
A manual transmission, also known as a manual gearbox or standard transmission is a type of transmission used in motor vehicle applications...
was universal in the Eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...
lines and was generally used with six-cylinder applications. All transfer cases were available with inputs matching either 21- or 23-spline shafts, so transmission swaps are possible among various models and years.
Manual
The following manual transmissions have been used in the vehicles listed above:- Aisin AX4 four-speed
- Aisin AX5 five-speed
- Aisin AX15 five-speed
- Borg-Warner HR1 four-speed synchronized unit (used only with the 121-4 engine)
- Borg-Warner SR4 four-speed synchronized unit (used only with AMC 6-cylinder engines and Pontiac 4-cylinder engines)
- Borg-Warner T4 four-speed (used only after 1981)
- Borg-Warner T5 five-speed (used only after 1981)
- Borg-Warner T10 four-speed
- Borg-Warner T14 three-speed
- Borg-Warner T18 four-speed
- Borg-Warner T85 three-speed
- Borg-Warner T96 three-speed
- Mercedes/Chrysler NSG370 six-speed (used after 2005)
- New Venture Gear NV1500 five-speed (used only with 2003–2004 2.4 L I4)
- New Venture Gear NV3550 five-speed (used only with 4.0 L I6)
- Peugeot BA-10/5 five-speed (used only with AMC 6-cylinder engines)
- Tremec T176 four-speed (used only with AMC 6-cylinder and 304 V8 engines)
- Tremec T150 three-speed
Automatic
The following automatic transmissions have been used in the vehicles listed above:- Aisin-Warner AW4 four-speed
- GM THM400 three-speed
- Chrysler 45RFE four-speed
- Chrysler 545RFE five-speed (used with 5.7L Hemi engineHemi engineA Hemi engine is an internal combustion engine in which the roof of each cylinder's combustion chambers is of hemispherical form.- History :...
and VM Motori 2.8L Turbo Diesel, same as 45RFE used with 4.7L but different software enabling a second overdrive) - TorqueFlite three-speed; used with the 4.2L I6 in most AMC cars
- TorqueFlite three-speed; used with the 2.5L I4 in most AMC cars
- TorqueFlite A727 three-speed; used in AMC Jeep/Eagle applications
- TorqueFlite 42RE four-speed
- TorqueFlite 44RH four-speed
- TorqueFlite 44RE four-speed
- TorqueFlite 46RH four-speed
- TorqueFlite 46RE four-speed
- Ultradrive 42RLE four-speed
Aisin-Warner
The Aisin-Warner four-speed automatic transmission (AW4) was selected by AMC in 1987 for use in the Cherokee XJ'sJeep Cherokee (XJ)
The Jeep Cherokee is a unibody compact SUV. It shared the name of the original full-size SJ model, but without a body-on-frame chassis, it set the stage for the modern SUV. Its innovative appearance and sales popularity spawned important imitators as other automakers began to notice that this...
new inline six-cylinder 4.0 L design. It was manufactured by Aisin-Warner
Aisin Seiki Co.
, also known as Aisin , is a Japanese corporation which develops and produces components and systems for the automotive industry. Aisin is a Fortune Global 500 company, ranked 347 on the 2007 rankings....
, a member of the Toyota group, in partnership with Borg-Warner
BorgWarner
BorgWarner Inc. is a United States-based worldwide automotive industry components and parts supplier. It is primarily known for its powertrain products, which include manual and automatic transmissions and transmission components, , turbochargers, engine valve timing system...
. 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 in³) AMC Straight-4 engine
AMC Straight-4 engine
The American Motors Corporation straight-4 engine was used by a number of AMC, Jeep, and Dodge vehicles from 1984-2002.*For an outline of all engines used by AMC see -Development:...
. 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
- 1987–1990 Jeep Comanche 2.5 L
- 1987–1992 Jeep Comanche 4.0 L
Chrysler/TorqueCommand
In 1970, AMC standardized a variation of the Chrysler-developed TorqueFliteTorqueFlite
TorqueFlite is the trademarked name of Chrysler Corporation's automatic transmissions, starting with the three-speed unit introduced late in the 1956 model year as a successor to Chrysler's two-speed PowerFlite...
transmission and called it the TorqueCommand. All TorqueCommand automatics used 23-spline output shafts. These transmissions were available in both the Chevrolet V6 pattern (used on the AMC 150 I4 and Iron Duke
GM Iron Duke engine
Iron Dukes were fitted with fuel injection in 1982. This version was christened the Tech IV, though Car and Driver later ridiculed it as the low-Tech IV. Power output remained at ....
I4 engines) and the AMC late model pattern that was used on their I6 and V8 engines.
Ultradrive 42RLE
The 42RLE, the version of the UltradriveUltradrive
The Ultradrive is a 4-speed automatic transmission from Chrysler Corporation. It was produced starting in 1989. It was originally paired primarily with the Chrysler 3.3 engine in vehicles with transverse engines...
transmission that was used by Jeep, evolved from the original A604/A606 Ultradrive. Per its model designation it contains four gears and a torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
rating of two. The 42RLE is a modified 42LE where as it is designed to mount longitudinally for rear wheel drive instead of transversely for front wheel drive. By design it has full electronic shift control with adaptive memory to learn the operator's driving habits controlled by the vehicle's Transmission Control Module (TCM). Contained within the automatic's torque converter is an Electronically Modulated Converter Clutch(EMCC) designed act as a shock absorber for harsh shifting.
Gear Ratios for the 42RLE:
- 1st: 2.80
- 2nd: 1.55.
- 3rd: 1.00
- 4th: 0.69
Models that used the 42RLE
- 2003–present Jeep LibertyJeep LibertyInspired by styling from the Dakar and Jeepster concept cars, the Liberty was intended as a replacement for the discontinued Jeep Cherokee . Three trim levels were initially offered; the top end Limited, a more rugged looking Renegade and the base Sport. All were made available with either 2WD or 4WD...
- 2003–present Jeep WranglerJeep WranglerThe Jeep Wrangler is a subcompact four-wheel drive sport utility vehicle and an off-road vehicle manufactured by American automaker Chrysler, under its Jeep marque – and now in its fourth generation. It is a successor to the famous World War II 'Jeep' vehicle by way of the Willys civilian...
Transfer cases
The transfer caseTransfer case
A transfer case is a part of a four-wheel-drive system found in four-wheel-drive and all-wheel-drive vehicles. The transfer case is connected to the transmission and also to the front and rear axles by means of drive shafts...
is an auxiliary
Auxiliary
Auxiliary may refer to:* A backup site or system* Auxiliary input jack, generally for audio* Auxiliary verb* International auxiliary language* Auxiliary police* Auxiliaries, troops supporting the main force of an army** Auxiliaries...
transmission that connects the front and rear axles. It also commonly provides a selectable secondary gear
Gear
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....
reduction
Reduction drive
A reduction drive is a mechanical device to shift rotational speed. A planetary reduction drive is a small-scale version using ball bearings in an epicyclic arrangement instead of toothed gears....
. 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 Right | 10 | 2.57:1 | THM400 | 1973–1979 |
| Dana 18 | Both Right | 6 (10) | 1.98:1, 2.42:1, 2.46:1 | Texas | 1940–1971 |
| Dana 20 | Front Right | 6 (10) | 2.03:1 | Texas | 1963–1979 |
| Dana 300 | Front Right | 23 | 2.62:1 | Round (New Process) |
1980–1986 |
| Atlas 2 Speed | Front Right or Left | Variable | 2.0:1, 3.0:1, 3.8:1, 4.3:1, 5.0:1 | Round (New Process |
Aftermarket Replacement |
| Atlas 4 Speed | Front Right or Left | Variable | 5.44:1, 8.16:1, 10.34:1, 11.70:1 | Round (New Process |
Aftermarket Replacement |
Borg-Warner 13-39/Quadra-Trac
The Borg-Warner 13-39 was a transfer case that could be substituted for the Dana 20. It was part of the first system that AMC marketed as Quadra-Trac. The basic version of the Quadra-Trac was the BW 13-05, which did not have a low range; instead, the optional low range of 2.57:1 was available by way of a planetaryPlanetary
Planetary means relating to a planet or planets. It can also refer to:* Planetary , a comic book series by Warren Ellis and John Cassaday* Planetary habitability, the measure of an astronomical body's potential to develop and sustain life...
reduction unit that bolts to the back of the transfer case. This assembly as a unit was designated as the BW 13-39.
The BW 13-39, which is often, but not always, imprinted with the casting number 13-39, was the first Jeep transfer case to be made of aluminum and to be chain-driven. The output for both the front drive shaft and the rear drive shaft is on the right side. This unique transfer case had an integrated limited-slip differential that splits power between the front and rear drive shafts. It used a vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
-operated differential that was available for use in both high and low range. A vacuum switch (usually located in the glove compartment
Glove compartment
A glove compartment or glovebox, also known as a little cupboard, is a compartment built into the dashboard, located over the front-seat passenger's footwell in an automobile, often used for miscellaneous storage. The name derives from the original purpose of the compartment, to store gloves...
) allowed the differential to be controlled by the driver.
The BW 13-39 was used only with AMC's version of the THM400 automatic transmission, which had a special extra-long 10-spline output shaft, between 1973 and 1979. It is not bolt-compatible with any other Jeep transmission.
Dana
Jeep has used three different transfer cases made by the Spicer Division of Dana Automotive Solutions Corporation. They are the 18, 20, and 300 models.Dana 18
The Dana 18 is a gear driven transfer case that has an offsetOffset
The term offset may refer to:* Carbon offset, a financial instrument aimed at a reduction in greenhouse gas emissions* Offset agreement, trade practice in Aerospace and Defense Industry...
rear output. All Dana 18 cases are cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...
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, 3" input hole
- 26-tooth input gear, 3/4" intermediate shaft and 2.42:1 low range, 3" input hole
- 26-tooth input gear, 1⅛" intermediate shaft and 2.42:1 low range, 3" input hole
- 26-tooth input gear, 1¼" intermediate shaft and 2.42:1 low range, 3" input hole
- 29-tooth input gear, 1¼" intermediate shaft and 2.46:1 low range, 4" input hole, Dana 20 case
The normal (3") input Dana 18s are interchangeable
Interchangeable parts
Interchangeable parts are parts that are, for practical purposes, identical. They are made to specifications that ensure that they are so nearly identical that they will fit into any device of the same type. One such part can freely replace another, without any custom fitting...
, 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.
All Dana 18s have front and rear outputs offset to the right side. Most vehicles built with a Dana 18 have the rear axle offset to the right side to accommodate this. Most other transfer cases used in Jeeps have a centered rear output that lines up with the input shaft. The Dana 18 always has gears turning, which makes it noisier then some other transfer cases when in two wheel drive mode.
Dana 20
The Dana 20 can be identified by the center rear output, cast ironCast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...
construction, and deep oil pan. Like the Dana 18, it uses the Texas bolt pattern to hold the transfer case in place. This is a heavy-duty, gear-driven transfer case with a 26-tooth input gear. The output for the front drive shaft is on the right side and the rear output is in line with the input. Its low range has a ratio of 2.03:1.
The Dana 20 is generally compatible with the "big hole" Dana 18. One exception is the version used with the THM400 in full-size Jeep trucks, which used a different spline number on the input gear.
Dana 300
The Dana 300 uses a round bolt pattern and has a nearly flat oil pan. It is a heavy-duty, gear-driven transfer case with a 23-spline input shaft. The case is cast iron but the tail housing is aluminum. The ID number C300-15 is stamped on the case. The output for the front drive shaft is on the right side and the rear output in line with the input. Low range is 2.62:1.One common modification of the Dana 300 is to add oil paddles to the main shaft to prevent oil starvation of the rear bearing.
The Dana 300 was used in Jeep CJs from 1980 to 1986. The 1980 factory original came with a shorter tail housing and a longer rear drive shaft. The Dana 300 should fit behind all TorqueCommand 4x4 transmissions.
New Process/New Venture
In general, New Process transfer cases are identified by a three-digit code. The first digit (1 or 2) determines the number of gearGear
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....
ranges
Ranges
Ranges - Lev. 11:35. Probably a cooking furnace for two or morepots, as the Hebrew word here is in the dual number; or perhapsa fire-place fitted to receive a pair of ovens. 2 Kings 11:8...
. The second digit is a series number that reflects design, and provides minimal information about torque handling. For example, if the second digit is a 1, there is no two wheel drive option; if it is a 2, 2WD is available. Other numbers have similar meanings. The third digit indicates differential type: 1 means locked (no differential), 2 means open, 3 means electric locked, 4 and 5 both indicate an asymmetrical torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
split planetary
Planetary
Planetary means relating to a planet or planets. It can also refer to:* Planetary , a comic book series by Warren Ellis and John Cassaday* Planetary habitability, the measure of an astronomical body's potential to develop and sustain life...
gear and gear drive, 6 means an electronic clutch pack, 7 means a hydraulic clutch pack (except for the unique 207), and 9 means a viscous coupler.
The AMC Eagle used three New Process transfer cases (Models 119, 128, and 129) that were single speed versions of the models (219, 228, and 229) that were used in 1980 and newer Jeeps. There was no difference between the Eagle versions and the Jeep versions other than the addition of a low range, indicated by the 2 as the first digit.
New Process transfer cases are chain-driven and use a circular 6 bolt, 23-spline input on the case. The output for the front drive shaft is on the left side. The New Process transfer cases used by AMC attach the same as the Dana 300 except that New Process cases have the front output on the left side. Interchange ('flip') is possible, but there is an indexing lug in the pattern, in an attempt to allow the transfer case to attach in only one position. Thus, some modification on the transfer case or the adapter is required.
Because of changes in the name of the manufacturing company, new versions of the NP231 and NP242 are referred to as NV (New Venture) or NVG (New Venture Gear).
| 119 | 128 | 129 | 147 | 207 | 208 | 219 | 228 | 229 | 231 | 241 OR | 242 | 247 | 249 † | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Full-Time High | Yes | Yes | Yes | Yes | No | No | Yes | Yes | Yes | No | No | Yes | Yes | Yes |
| High Lock | No | No | No | -- | Yes | Yes | Yes | No | No | Yes | Yes | Yes | No | No |
| Low Range | No | No | No | No | 2.61:1 | 2.62:1 | Yes | Yes | Yes | 2.72:1 | 4.0:1 | 2.72:1 | 2.72:1 | 2.72:1 |
| 2wd | No | Yes | Yes | No | Yes | Yes | No | Yes | Yes | Yes | Yes | Yes | No | No |
| Differential | Viscous | Open | Viscous | Gyro-Clutch | Locked | -- | Viscous | Open | Viscous | Locked | Locked | Open | Gyro-Clutch | Viscous |
↑ The 249 was available in two versions. The early (1993–1996) version had no differential lock and the viscous coupling spanned the center differential, creating a 50/50 torque split. The later version (1996 and beyond) had a viscous front drive, creating a rear torque bias, but included a provision to lock the center differential.
Overdrives and underdrives
Borg-Warner/Quadra-Trac overdrive was available from early 1960 to 1969. The Borg-Warner overdrive case is 11¾ inches long (less torque tube adapter, if required), including the 1+1/2 in adapter. A complete T96 with overdrive is 18¾ inches long from front of case to end of tailshaft housing. The overdrive unit is the same for all.The Dana 18 has a Power take-off
Power take-off
A power take-off or power takeoff is a splined driveshaft, usually on a tractor or truck, that can be used to provide power to an attachment or separate machine. It is designed to be easily connected and disconnected...
(PTO) attachment on the case that can be used to drive equipment that accepts PTO input. A unique feature of the Dana 18 is the overdrive that attaches in the PTO port in the back of the system. An adapter allows use of both the overdrive and the PTO attachment, but it is no longer produced.
Laycock-DeNormanville overdrive was available from 1974 through 1976 for inline six with the 150T and V8 torque tube cars with the T89.
Transmission to transfer case adapters and clocking
Transmissions end with a splined tail shaft, more commonly called an output shaft. When one or more auxiliary units are bolted to the main transmission, these are called adapters, extension housings, or tail housings. All factory applications with a four wheel drive transfer case require an adapter, and many upgrade transmissions that would otherwise be incompatible can be adapted to Jeep transfer cases.Clocking refers to the angle at which the transfer case is tilted with reference to the horizontal plane. Stock Jeep clocking for the Dana 300 (1980–1986) is usually 23° and stock Eagle and Jeep/New Process clocking is usually 13°. Many factors, most notably ground clearance and front drive shaft clearance, can necessitate a change in the clocking angle. Some aftermarket adapters, such as those manufactured by Novak Conversions feature flanges with multiple clocking options.
Bell housings
The bell housingBell housing
"Bell housing" is a colloquial/slang term for the portion of the transmission that covers the flywheel and the clutch or torque converter of the transmission on vehicles powered by internal combustion engines. This housing is bolted to the engine block and derives its name from the bell-like...
bolt pattern for the old AMC 196 Straight-6 engine is the same as for the more modern 199 and 232 (used in 1964–1971), but the 196 had different dowel pin sizes. When AMC dropped the GEN-1 V8 engines in 1966, the bell housing changed, but all later V8 bell housings are the same. The bell housing for six cylinder engines changed to match the V8 in 1972 when AMC switched from Borg-Warner to Chrysler transmissions. The flywheel also changed from 153 teeth (a common Chevy size) to 164 teeth (a common Ford size).
The Iron Duke I4 transmission bolt pattern varies between the Chevrolet Small Six and the BOP (Buick, Oldsmobile, Pontiac). The later AMC I4 had a Small Six bolt pattern, and this was retained for the life of the engine. AMC often used lighter duty transmissions with these engines.
| Engine family | Bell housing style | Flywheel/Flexplate |
|---|---|---|
| GEN-1 V8 Engines | AMC GEN-1 V8 | -- |
| Early AMC I6 | AMC GEN-1 I6 | 153 teeth |
| Willys 230 I6 | Continental Continental Motors Company Continental Motors Company was an American engine and automobile manufacturer. The company produced engines for various independent manufacturers of automobiles, tractors, and stationary equipment from the 1900s through the 1960s. Continental Motors also produced Continental-branded automobiles in... |
-- |
| GEN-2 and 3 V8s AMC V8 engine American Motors Corporation produced a series of widely-used V8 engines from the mid-1950s before being absorbed into Chrysler in 1987. Chrysler kept the AMC V8 in production until 1991 for the Jeep Grand Wagoneer.... |
AMC Late Model | 164 teeth |
| Modern AMC I6 | AMC Late Model | 164 teeth |
| Buick 225 V6 | BOP V8 | 153 teeth |
| Iron Duke | Chevrolet V6/V8 | -- |
| AMC 150 I4 AMC Straight-4 engine The American Motors Corporation straight-4 engine was used by a number of AMC, Jeep, and Dodge vehicles from 1984-2002.*For an outline of all engines used by AMC see -Development:... |
Chevrolet V6 | -- |
See also
- Jeep four wheel drive systemsJeep four wheel drive systemsJeep uses a variety of four-wheel drive and all-wheel drive systems on their various vehicles. These range from basic part-time systems that require the driver to move a control lever to send power to four wheels, to permanent four-wheel systems that monitor and sense traction needs at all four...
Companies
- American MotorsAmerican MotorsAmerican Motors Corporation was an American automobile company formed by the 1954 merger of Nash-Kelvinator Corporation and Hudson Motor Car Company. At the time, it was the largest corporate merger in U.S. history.George W...
- JeepJeepJeep is an automobile marque of Chrysler . The first Willys Jeeps were produced in 1941 with the first civilian models in 1945, making it the oldest off-road vehicle and sport utility vehicle brand. It inspired a number of other light utility vehicles, such as the Land Rover which is the second...
- Willys-Overland
- Kaiser MotorsKaiser MotorsKaiser Motors Corporation made automobiles at Willow Run, Michigan, United States, from 1945 to 1953. In 1953, Kaiser merged with Willys-Overland to form Willys Motors Incorporated, moving its production operations to the Willys plant at Toledo, Ohio...
- AM GeneralAM GeneralAM General is an American heavy vehicle manufacturer based in South Bend, Indiana. It is best known for the civilian Hummer and the military Humvee, that is assembled in Mishawaka, Indiana...
Parts
- New Venture GearNew Venture GearNew Venture Gear, a division of Magna Powertrain, is a automobile transmission company. It was founded in 1888 under the name "New Process Gear" then in 1934 it was purchased by Walter Chrysler. In 1999 New Process Gear was renamed "New Venture Gear" when it became a joint venture between General...
- Transfer caseTransfer caseA transfer case is a part of a four-wheel-drive system found in four-wheel-drive and all-wheel-drive vehicles. The transfer case is connected to the transmission and also to the front and rear axles by means of drive shafts...
- TransmissionTransmission (mechanics)A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
- TorqueFliteTorqueFliteTorqueFlite is the trademarked name of Chrysler Corporation's automatic transmissions, starting with the three-speed unit introduced late in the 1956 model year as a successor to Chrysler's two-speed PowerFlite...