Information on Manual Transmissions for Jeeps

The T90 is the most famous of the Jeep three-speed transmissions

• Compatible with Willys I4 & I6 engines and adaptable to GM engines
• Iron case and top cover. Close-ratio first gear with direct-drive in third-gear
• Fairly strong and extremely compact
• Compatible with the Dana 18 and easily adaptable to the Dana 20
• 1946-1971 Jeeps

The T86 is kind of a T90 knock-off. It was the transmission first offered with the Buick V6 engine

• Compatible with the Buick V6 engine
• Iron case and top cover. Close-ratio first gear with direct-drive in third-gear
• Moderately strong and compact
• Compatible with the Dana 18 readily Dana 20
• 1946-1971 Jeeps

The T14 is the T15's little brother. Not too tough but a pretty good gearbox

• Native to Buick then AMC engines and adaptable to GM engines
• Iron case and top cover. Close-ratio first gear with direct-drive in third-gear
• Moderate strength and fairly compact
• Compatible with the Dana 18 & 20
• 1968-1975 Jeeps

The T15 was the strongest of all the three-speeds

• Compatible with AMC engines and adaptable to GM engines
• Iron case and top cover. Close-ratio first gear with direct-drive in third-gear
• Very strong and quite compact
• Compatible with the Dana 20
• 1972-1975 Jeeps

The T150 was strong, and the last of the Jeep three-speeds

• Compatible with AMC engines and adaptable to GM and Ford engines
• Iron case and top cover. Close-ratio first gear with direct-drive in third-gear
• Fairly strong and extremely compact
• Compatible with the Dana 20
• 1976-1979 Jeeps

The GM SM465 is said to be one of the greatest four-speeds ever built.

• Compatibility with GM and AMC style engines
• Iron case and top cover. Deep first gear with direct-drive in fourth
• Brutally strong, but refined for road and trail manners
• Adaptable to essentially all of the Jeep transfer cases
• 1968 - 1991+ GM trucks

The Borg-Warner T18 & T19 transmissions are famous in the truck and off-road world, and this reputation is well earned.

• Compatibility with GM, Ford and AMC style engines (Ford & Jeep versions)
• Iron case and top cover. Deep first gear with direct-drive in fourth
• Extremely strong, but with good road and trail operaion
• Adaptable to essentially all of the Jeep transfer cases
• 1966 - 1991+ Fords & Jeeps, primarily

The New Process 435 is a supremely good four-speed with an excellent history

• Compatibility with GM, Ford, Dodge and AMC style engines
• Iron case and aluminum top cover. Deep first gear with direct-drive in fourth
• Tough as nails, but shifts nicely on the street and trail
• Adaptable to essentially all of the Jeep transfer cases
• 1966 - 1991+ Dodge & Ford trucks, primarily

The SM420 is the great predecessor of the four-speeds and remains a great choice for several Jeep applications.

• Compatibility with GM and AMC style engines
• Iron case and top cover. Deep first gear with direct-drive in fourth
• Extremely strong, but quite roadworthy
• Adaptable to essentially all of the Jeep transfer cases
• 1947 - 1967 GM trucks

The T98 transmission is the predecessor to the T18 and similar in appearance and design

• The Jeep version is adaptable with GM engines
• Iron case and top cover. Deep first gear with a direct-drive in fourth gear
• Plenty strong for any Jeep
• Retained with the native Jeep transfer case
• 1955 - 1971 (in Jeeps)

The T176 (and T177 / T178) is native to 1980 - 1986 Jeeps as the medium duty upgrade

• Compatibility with AMC I4 & I6 engines, and adaptability to GM and Ford engines
• Aluminum case and top cover. Close-ratio first gear with direct-drive in fourth gear
• Stronger than the base-option transmissions during this era
• Compatible with the Dana 300
• 1980-1986 Jeeps

The SR4 is a car transmission that was installed in CJ Jeeps for two years

• Compatible with AMC I4 & I6 engines
• Aluminum case and top cover. Close-ratio first-gear and direct-drive in fourth
• Neither strong, nor suited to conversions or serious off-road use
• 1980-1982 CJ Jeeps

The T4 was the standard four-speed in the 1982-1986 CJ

• Compatible with AMC I4 & I6 engines
• Aluminum case and top cover. Close-ratio first-gear and direct-drive in fourth
• Neither strong, nor suited to conversions or serious off-road use
• 1982-1986 CJ Jeeps

The AX15 is a surprisingly strong transmission, and was a serious improvement over many of its lighter-duty predecessors

• Compatibility with AMC I6 and other engines, and adaptability to GM and Ford engines
• Aluminum case. Decently low first gear with overdrive in fifth-gear
• Surprisingly tough
• Compatible with the NP231 and adaptable to the Dana 300, Dana 20 and Dana 18
• Originally came in 1988-1999 Jeeps

The NV3550 was New Venture's answer to the AX15, and in the same strength, operational and size category

• Compatibility with AMC I6 engines, and adaptability to GM and Ford engines
• Aluminum case. Good first gear with overdrive in fifth-gear
• Reasonably strong
• Compatible with the NP231 and adaptable to the Dana 300, Dana 20 and Dana 18
• 2000-2004 Jeeps
• Not as desirable as its predecessor, the AX15

The NV4500 is a heavier-duty five-speed as found in full size GM and Dodge trucks

• Compatibility with GM & Dodge engines with adaptability to AMC engines
• Iron case with aluminum top cover . Fairly low first gear with overdrive in fifth-gear
• Quite strong
• Adaptable to the Jeep Dana 300 and NP231
• 1993-present GM and Dodge trucks

The T5 was the standard five-speed in the 1982-1986 CJ

• Compatible with AMC I6 engines
• Aluminum case and top cover. Close-ratio first-gear and overdrive in fifth gear
• Neither strong, nor suited to conversions or serious off-road use
• 1982-1986 CJ Jeeps

The AX5 was the light-duty, five-speed transmission in the 1984-2003 XJ, YJ & TJ Jeeps

• Compatible with AMC I4 engines
• Aluminum case and top cover. Close-ratio first-gear and overdrive in fifth gear
• Neither strong, nor suited to conversions or serious off-road use
• 1984-2003 XJ, YJ & TJ Jeeps

The Peugeot BA10/5 had a gratefully short run in Jeeps

• Compatible with AMC I6 engines
• Aluminum case and top cover. Close-ratio first-gear and overdrive in fifth gear
• Neither strong, nor suited to conversions or serious off-road use
• 1987-1988 XJ, YJ & MJ Jeeps