AW4 tailshaft housing on an AX15? (4wd conversion)

I've been reading about 4wd conversions and understand you need to pull the tailshaft housing off the 2wd transmission and swap one from a 4wd trans to mount the t-case to it. I also understand that this is possible for some transmissions, but not for others. I'm looking at a '94 XJ with AX-15. My question is, can the tailshaft housing from a 4wd AW4 mount (by some stroke of pure luck) to an AX-15 trans? Beyond that, do they have a different spline count?

I know it sounds like I'm going around my elbow just to get to my nose, but where I live it is extremely rare to find a 4wd with AX-15, but 4wd with AW4 are everywhere for cheap. I just located a nice 2wd manual locally, so I thought I'd ask. I'm even considering just getting that and a locker for the rear and just going with it!

Thanks for your help - I'm desperate to get back into an XJ!

Best bet, find a 4WD AX-15, and there are plenty around.

Converting a 2WD gearbox/slushbox to 4WD isn't (typically) merely a matter of swapping the tailcone for the transfer case adapter housing.

The mainshaft (manual) or output shaft (auto) is generally a few inches shorter, and the splines are usually different as well. So, you're looking at overhauling the box.

Probably better to get a 4WD box if you don't think you can handle it. Since most automatics are front-loading, you have to gut the thing entirely. The mainshaft in a manual runs most of the length of the case (it's in line behind the input - the input shaft drives a countershaft, the countershaft has all of the ratio gears on it, and the shifting is usually done there by engaging the desired gear with a synchroniser ring and a drive ring.) The mainshaft is usually retained by either an intermediate plate (typical) or a bearing journal (clamshell case) at the front end, and a bearing in the tailcone/adapter housing at the rear - so you probably have an idea already what replacing that entails.

And, generally, different transmission makes and models have different mounts for the bellhousing and tailcone, so they're note likely to swap.

However, you can get the 2WD AX-15, and look for a 4WD AX-15 in some Toyota pickups, some early V6 Durango, and possibly some early 4.3L V6 S-series GM - the box is the same, I believe they're all 23-spline outputs, and you can simply swap the bellhousing (as I believe they all use a 1.125-10 input shaft of the same length and pilot dimensions.) They're all AX-15, so the bellhousings will swap handily. Just make sure it's the same version of the AX-15 - it used an "internal" slave cylinder (combination slave cylinder and throwout bearing) through 1993, and went to an "external" slave (seperate units) starting in 1994. The bellhousings and front bearing retainers are different.

Johnnie Walker said:

Best bet, find a 4WD AX-15, and there are plenty around.

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Maybe in California, but not here.

5-90 said:

However, you can get the 2WD AX-15, and look for a 4WD AX-15 in some Toyota pickups, some early V6 Durango, and possibly some early 4.3L V6 S-series GM...

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Thanks for all the advice, very good to know. Obviously it would be best to just find a manual 4wd and that's what I'm hoping to do, but I'm just trying to learn about all my options. Thanks for your time!