i am pretty sure the parts you need for a swap can be pulled from a cherokee. the mj is supposed to be the same from the doors forward, so a 4wd conversion should be the same as on an xj. i think all you need is a 4wd tranny, transfer case, front axle with the same gearing as the rear, driveshafts, shift lever and wiring harness for the 4wd. i am considering doing the same, so hopefully someone who knows for sure or has done it will chime in. if not, try comancheclub.com
MJ and XJ front axles are the same. But you have get the same gearing, the 4.0L had auto: 3.55, manual: 3.07, and 2.5 had manual: 4.10s I believe, don't recall for the auto but, likely 3.55. You would need the t case, the rear and front drive shaft, and of course, the front axle. So, ideally find an MJ with the same motor and trans as yours and take what I mentioned above and you're set! Unless I'm forgetting anything?
Don't forget the bracket for the linkage for the 4wd shift lever. The front axle and driveshaft are identical to XJ. You will need a 4wd transmission or change over the rear section of your tranny. Easier to get the whole tranny. If your MJ is 4.0, then make sure you get the drivetrain components from a 4.0. If not, the tranny and transfer case will be weaker and incorrect number of splines if you are mixing/matching. The driveshaft will need to be from a correct bed length MJ or have yours shortened. Good Luck!
We started on doing this today.
All the parts came from a 91 XJ, AX15, NP231 and 3.07 gears.
EVerything has be a straight forward swap except the transfer case shifter pivot bracket it takes a
fiddling, I just got it in place and sprayed some paint over it. I had instant whole placement.
I was able to use the 2wd speedometer cable it barely reaches.
The driveshaft will have to be cut down somewhere between 9 and 10 inches I havn't got that
far yet. We got agitated this evening with a blown hydraulic hose on the clutch.
I alos have to add that the xfer case sfiter holes did not line up nicely with the mj cover either.
You also need the tranny mount from the XJ if your going from a BA5/10 to an AX15 like we did.
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I've been involved with 5 over the years, bought rolled or wrecked XJs and had everything right there, easy swap, then cut the body up and send it on its way. We even used the interiors/consoles, later model front clips on two of them. Everything swaps over easy enough
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