Jeep AX15 manual transmission swap

David Banks
Authored by David Banks
Posted Friday, May 14, 2021 - 11:35pm

It’s important to look at what your Jeep is equipped with. You want all of the strength that you can possibly get, especially if you’re planning on driving on rugged terrain. The AX5 is the standard transmission, and it’s a light-duty one. The moment you equip your Jeep with such things as larger tires and lower gears, you’ll want added drivetrain strength – and that’s when you’ll want to swap in a rebuilt AX15 manual transmission.

Making the swap is relatively easy, though you’ll want to know how to handle the modification from start to finish.

Start with getting an AX15 bellhousing

You’ll need to get your hands on an AX15 bellhousing – and the adapter kits on the market will make it easier for you to focus on the conversion. Be sure that you buy the kit based on the year of your Wrangler.

Advance Adapters has a lot of great kits that provide you with everything. However, if you go with other kits on the market, you’ll also need an adapter plate. This means that you’ll want to pay close attention to what it is that you’re buying.

When you’re making the switch to the AX15, you’ll want to throw out the bearing fork. This also means that you’ll want to get something beyond the transmission – a short-throw shifter and a new internal throwout release bearing. As you’re buying supplies, it’s a good idea to get some 10W30 Mopar oil as well.

The steps to making the swap

Once you have the AX15 transmission and the various parts that you’ll need (based on whether you buy a kit or the individual parts), there are a few steps you’ll want to follow:

  1. Measure the OD of the input shaft so you know what pilot bushing ID you’ll need. 0.75” is a common size, which would require an AA pilot bushing.
  2. Remove the AX5 transmission. Depending on your Jeep model, you may have to remove the muffler assembly, too (such as with a YJ).
    • Engage the parking brake.
    • Disconnect the negative lead of the battery
    • Support your transmission with a jack stand
    • Remove the bolts and supports, then unplug all of the electrical connections to the transmission and transfer case
    • Remove the center console, the shifter lever, the transfer case shift linkage, and the four bolts that secure the rear drive link to the yoke on the rear axle.
    • Remove the four bolts that secure the front driveshaft to the yoke on the transfer case
    • Remove the front driveshaft
    • Remove the nuts that secure the clutch slave cylinder (but don’t remove the slave cylinder from your Jeep)
  3. Prepare the AX15 so that it’s ready to go into the Jeep.
    • When the 4.0 bellhousing is still on the AX15, it can be removed by detaching the clutch fork.
    • Install the new bellhousing with 13mm bolts.
    • Install the throwout bearing to the clutch fork and then grease the snout of the bearing. The clutch fork should be clipped over the clutch fork pivot ball.
  4. Continue with the installation, including the clutch and pilot bearing.
    • You’ll want to remove the pressure plate and clutch
    • Inspect both for damage
    • Remove the pilot bearing so that you can install the pilot bushing. Utilize the pilot bearing alignment tool so that you can align the clutch disk. Once in place, put the pressure plate back into position and torque to the required specifications.
  5. Install the AX15
    • Secure the transmission to the transmission jack under the Jeep.
    • Align the transmission so that the input shaft is aligned with the clutch and pilot bushing. Use the alignment dowels, as necessary. Rotate the output shaft so that the clutch teeth engage with the input shaft.
    • Install the bellhousing bolts and torque to specifications
    • Install the bellhousing dust shield.
    • Reinstall the starter.
    • Retighten the clutch slave cylinder.
  6. Finish with the reconnections
    • Install the shift lever, following the opposite directions as you used to remove it.
    • Raise the transfer case into position with the help of the transmission jack. Once all is aligned, use washers and nuts and torque to specifications.
    • Reinstall all of the electrical connections to the engine and the transmission.

Depending on other modifications, you’ll also want to consider the installation of a cable shifter as well as installing adjustable upper control arms.

Once you’re finished, lower the jack and jack stand. Reinstall the center consul and check the clearance with your shift lever. If you want to retain your AX5 shifter, there is a spacer plate so that you’re not in odd gears.

There are also a few tips that will help you along the way:

  • Completely disassemble the transfer case. This will be the only way for you to install the input shaft. While there are YouTube videos to help, you’ll want wrenches and cheater bars to help you get the front yoke off effectively.
  • You’ll need to bleed the slave cylinder to remove air pockets from the hydraulic system.
  • When you’re reassembling the transfer case, be sure that you have RTV sealant.

What to expect after the swap

Once you get rid of the old AX5, you’ll find that it should drive in almost the same fashion as the AX15. However, you will find that the shifting is both firmer and crisper. Plus, it will have a stronger transmission. The accelerations and downshifts should all feel the same as they did before the swap.

Of course, if you’re having problems or you’re noticing oil leaking, you’ll want to bring it to the mechanic. They’ll be able to diagnose and see what went wrong so that you’re up and running again as quickly as possible. For more information on other Jeep transmissions check out

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