The AX-15 Jeep Manual transmission manufactured by Aisin-Warner is a medium-duty, standard shift, 5-speed transmission and has been very successful. Its introduction led to the usage in jeeps from 1988 to 1993. Both 2wd and 4wd versions of Jeeps contained the transmission.

This is still a very popular manual transmission.


The following are the features of the AX15.

  • A split-case
  • Top shift
  • Overdrive transmission s
  • Shifter located in the rear section of the transmission
  • Fully synchronization in all gears
  • Helically cut gear
  • Gear ratios from the first to fifth are 3.83, 2.33, 1.44, 1.00, and 0.79.

Identification of the Jeep AX-15 Manual Transmission

The length of the transmission case in the 4wd version is 16-1/2-inch. In the same version, there is a 23 spline output shaft to connect the transfer case input shaft and the shaft points out approximately half an inch out of the rear face.

The case is made of cast aluminum with a cast-aluminum mid-plate. Dowel pins are used for bell housing alignment in the newer AX15. Both AX15 and AX5 have the same appearance making people to sometimes confuse them and use interchangeably.

Transfer Case Compatibility

A factory-based union was established between the Jeep AX15 and Jeep New Process called New Venture, Model 231 transfer case.

The marriage of AX15 to the NP207 transfer case has been possible in some Jeeps but with some modification.  Check with a professional dealer and see what can be done.

Bell housing Adaptability

Just as we have the marriage of the AX15 to the Jeep engines aforementioned, there is OEM compatibility between them. People who have a hope of the replacement of their AX5 sometimes assume that the AX15 will be a direct replacement.

There is close similarity that deceives in the bell housing patterns and spline counts of transmissions having the same appearance. However, there exists no compatibility.

As for GM engines, a good conversion to them is possible with the AX15. It is suitable for engines like Chevy V6, Chevy Small Block V8 and Gen. III+ V8 because of the stronger transmission. It is also applicable to Ford.

It is possible to use a kit (ask a dealer) to have a clean adaptation of AX15 to Windsor Ford V8 and Ford I6 bell housing that are characterized by the “butterfly” Ford transmission bolt pattern.

Transmission Fluid

As stated in the factory manual, there is a need to apply 75W90 GL-3 gear oil for the AX15 transmission. According to the experience of certain people, a 50W fluid makes provision for quicker shifts. This is more realizable in colder climates.


As regards Jeep transmissions, the AX15 is in the list of good achievements. For most enthusiasts, they regard it as the best 5-speed transmission ever installed into a Jeep.

The excellent gearbox is one of its features and continues to be produced by Aisin-Warner.

Categories: Automotive

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