XJ to MJ 4wd drive conversion

Ok so lately I have been thinking more and more about getting truck. While a mid 90's Toy would be nice it would be a huge project with a lot of extra expenses to go solid axle, lockers, gears, get rid of the birfeilds yada yada yada.
On the other hand if I were to get a MJ then I can transfer a lot of the parts off of my XJ to it and then part out the rest and take the XJ to the local salvage yard. The down side to the MJ is there is no "extra-cab which is nice for intertior space.
Now here is my question:
I have a line on a MJ for $500 with something like 90k on it but...... it is 2wd.
How hard is it (ie: who has done it) to take my drivetrain off of my XJ and put it on the MJ? Would it be worth it?

It is all bolt on! Did it in one weekend. Installed a lift at the same time, axles came out of a wrecked 92 4cyl with the non disco HP housing, trany and t-case came out of a 91 chero. The only thing I forgot to nab was the center console. It is the easiest vehicle to convert from 2wd to 4wd. I did it about 4 years ago, but still remember most of it. If you have any ?'s send me an e-mail. [email protected]

I guess what I am worried about is that I have three variables here: XJ->MJ, 2wd->4wd, Non HO->HO (I don't know how well it runs if it runs at all). If it runs good then I will just leave the engine as is.

If you have a HO motor in your current XJ, and it runs great, change it all. The 2wd XJ, MJ has a solid axle tube like a traler with the exact same control arm set up. It just has the long tail 2wd AW-4 tranny (or stick of choice, long tail). I don't anything about the DS.

Now what kind of parts would I get from somebody's rolled XJ,

XJCHUCK72 said:

Now what kind of parts would I get from somebody's rolled XJ,

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How about a slush box? Then Gary would get off of your case

Slush box? Anyway where can I find some leaf spring plates for my D44?

I'm almost done with the conversion on my MJ, and I have to say it really is a bolt-in job, pretty simple. I've put about three days total work into it, but it's taken a few months total because the truck is 300 miles away from me (long story...)
Couple hints to help you..you'll need a longer speedo cable than your 2WD one, try to use a non-disco axle for simplicity sake, good time to do a clutch/release bearing replacement while you have it all apart, and you'll need a shorter MJ 4WD driveshaft. The XJ shaft will work, but the MJ shaft is alot larger diameter, so I'm keeping my XJ shaft as a spare and having my MJ shaft cut down.
Good luck, and e-mail me if you have any q's.
Jeff

What engines are in there Jeeps? Are they both 4.0Ls? What about trannys? Changing between 2.5L to 4.0Ls and sticks and autos can be reeeeal pains in the butt.
Jeep on!
--Pete

I have a question about a very similar swap. I am looking at an 88 MJ 2wd, 4.0, 4spd. I have a front axle, transfer case etc. from a 99' xj. The XJ had an AW4 trans. what would have to be done to use the NP231 case from the 99' on the 4spd trans in the 88'? Thanks for any help.

xjparts said:

I have a question about a very similar swap. I am looking at an 88 MJ 2wd, 4.0, 4spd. I have a front axle, transfer case etc. from a 99' xj. The XJ had an AW4 trans. what would have to be done to use the NP231 case from the 99' on the 4spd trans in the 88'? Thanks for any help.

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If you have a 4.0L MJ with a 4-speed tranny, it is not a factory tranny. The 4.0L was never sold with a 4-speed manual. Or did you mean a 4-speed automatic, in which case it's an AW-4 just like the one in the XJ.

The difference will be that the '88 will have a 21-spline transmission to transfer case shaft, and the '99 will be 23 spline. This is kind of academic, since the 2WD tranny needs a completely different output to mate up with the transfer case. It's both easier and probably cheaper to just buy a 4WD tranny from a junk yard than to try to convert the 2WD tranny to mate with a transfer case. Just be sure to buy a tranny that mates to your transfer case.