The Novak Guide to the
Borg-Warner T4 & T5 Transmissions
The Borg Warner T4 & T5 transmissions were standard shift, four-speed & five-speed transmissions (respectively) found in 1982 to 1986 Jeep CJ models. They are light-duty transmissions found behind the AMC 150 (2.5L) I4 and the AMC 258 I6 (4.2L).
The T4 / T5 is a top loaded, top shifting transmission with the shifter being located in the rear section of the transmission. It is fully synchronized in all gears. All gears are helically cut.
The T4 / T5 transmission case is 9-1/4" long in addition to its 6" shifter / tailhousing assembly; for a 15-1/4" total length. It features a cast aluminum top cover that is retained by eleven bolts and a main case of cast aluminum.
The Jeep T4 / T5 has a 23 spline output shaft for connecting to the transfer case input shaft. The transmission has a 7-1/2" input shaft (stick-out length) with a 1-1/8" x 10 splines.
Typical Borg Warner casting numbers found on the T4 are 13-51 and 13-52 for the T5. The shifter is curved, instead of an angular bend like the T176. The transmission is the progeny of the SR4, so they look similar and are occasionally confused.
Later T4's and T5's have a larger front countershaft bearing. The earlier version is denoted by a "-102" suffix and the later version is denoted by a "-202" suffix.
A strengthened version of the T5 called the "World Class" was available and parts were formerly available to address some of the transmission's weaknesses. However, even with these, splines shear and the cases stretch under torque and no such upgrades could prevent some failures.
Transfer Case Compatability
The Jeep T4 & T5 was factory-married to the Jeep Dana Spicer Model 300 transfer case.
Because of the weaknesses of this transmission, we do not make adapter assemblies to join it to other transfer cases.
As the T4 / T5 was married to the Jeep engines mentioned above, it is OEM compatible with them.
Because of the transmission's weak service record behind stock Jeep powerplants, we do not offer any conversion to V6 or V8 power. This is essentially a small car transmission in a truck. The customer's time and efforts are best spent converting to a stronger transmission. These details are discussed in this article.
You may also wish to read Conversions We Don't Do.