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The Novak Guide to the

Borg-Warner SR4 Transmission

sr4_transmissionThe Borg Warner SR4 transmission was a standard shift, four-speed transmission found in 1980 to 1981 Jeep CJ models. It is a light-duty transmission found behind the 151 Iron Duke I4 and the AMC 258 I6.

This transmission is popularly replaced with the SM420 and SM465 transmissions, since they share a similar bellhousing bolt pattern and compact installations.


The SR4 is a top loaded, top shifting transmission with the shifter being located in the rear section of the transmission. The SR4 is fully synchronized in the first through fourth gears. All gears are helically cut.


The SR4 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 SR4 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). AMC 258 I6 and GM 151 I4 engine versions have a 1-1/8" x 10 splines. The AMC 2.5 I4 engine version has a 1" x 14 spline input shaft.

sr4_specsTypical Borg Warner casting numbers found on the SR4 are 13-32 for six-cylinder Jeeps and 13-40 for four-cylinder Jeeps.

  • RF D9ZR-7222-AA
  • RF D5ZR-7006-BA
  • 13-32-097-90
  • 13-40-097-902

The shifter cane is curved, instead of having an angular bend like the T176. The SR4 is the predecessor to the T4 & T5, so they look similar and are occasionally confused. 


Transfer Case Compatibility 

The Jeep SR4 was factory-married to the Jeep Dana Spicer Model 300 transfer case.

Because this transmission is lighter-duty, we do not make adapter assemblies to join it to other transfer cases.

Bellhousing Adaptability

AMC Jeep 

As the SR4 was married to the Jeep engines mentioned above, it is OEM compatible with them.


Because of the transmission's 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.