2wd to 4wd conversion

has anybody ever done a 2wd to 4wd conversion? i have a guy thats getting rid of his 90 mj 2wd for $300. is it worth purchasing and converting it to a 4wd?

For 300 definitely, is it a standard or an auto?

I did a standard + 4x4 conversion at the same time on mine, the only part you need that you can't get out of a donor XJ at the junkyard is the rear driveshaft and you can simply cut your old one down to length or have the pros do it for like 120 bucks.

How long did it take you to do the swap? I need to do this to mine in the future; not the standard part, though.

Front axle took me about 4-5 hours working alone, but I was being quiet and going slow and drinking a lot of beer. I did this swap in stages:
* swapped front axle in instead of the beam. 4-5 hours. Mostly because my track bar bolt was rusted and stuck and I had to very carefully grind off the nut on my drag link at the knuckle without wrecking the threads on the TRE stud, it was too badly rusted to get a socket on it. You won't need to worry about this obviously. I did the axle and then drove it around with my awesome dana 30 2wd beam for about a year because I didn't have time to swap the trans yet.
* swapped the trans and transfer case. I would say this took me around 15 to 20 hours because I had to build a custom wiring harness to disable the NSS and get my reverse lights back, and had to swap out all the automatic stuff and swap in all the manual stuff, including the clutch pedal, drilling holes in the firewall, etc. I also pulled and replaced the motor at the same time as well as the radiator, steering box, power steering pump, and a lot of other parts because they were due for replacement and my motor mount bosses had broken off from deathwobble. I would budget about 5-10 hours to swap in the trans, transfer case, and front driveshaft.
* installed lift and new rear axle, set pinion angle, and shortened driveshaft to the proper length. This probably took me about 4 or 5 hours, it should take you way less because you just have to shorten the driveshaft or get it shortened... in fact I would just tape a cokebottle over the transfer case output housing, toss the driveshaft in the bed, and drive it to a driveline shop, then ask them to cut it to the right length. I did it myself because I have a welder (do you? I forget) and it came out OK, aside from vibes above 75 because I was an idiot and welded the yoke back on 70 degrees out of phase :dunce: I was in a hell of a hurry trying to get the thing ready for a trail run the next day and completely forgot to line them up.

If I was going to do it again on a stock height truck without the 5spd swap and had a flat driveway to do it on instead of my back porch, I believe I could get the whole job done in ~15 hours working alone. That's pulling the motor and drivetrain out the front because I absolutely hate wrestling with a transmission under the truck.

Special tools you'll want - E12 inverse torx, good torx set (some jeeps have UCA bolts with torx heads), 5/16" gearwrench (front CV yoke bolts), 9/16" gearwrench with a flex head (transfer case to transmission stud nuts), 15mm gearwrench with a flex head (torque converter to flexplate bolts), 11mm socket, wobble joint, and a million feet of extensions if you are doing the trans from under the truck (CPS bolts.)

You should keep in mind the year splits for donor vehicles - don't know em too well for standards, but ideally I would go with a 91-95 AW4 and NP231 from the same vehicle since you'll get a more modern 23 spline setup with better parts availability, and the rear output on the transfer case will be compatible with the yoke on your rear driveshaft. Ideally you should get the front axle from a 91-94 with ABS or any 95-99 (specifically a 99.5 if you are also planning a WJ steering/brake swap at some point in the future.) A lot of this doesn't have much to do with doing the 4wd swap, but you might as well get parts that save the most time/money for other swaps you might do in the future IMO.

Absolutely worth it! Heck, even it you leave it 2wd, and just use it as a parts hauler for your XJ! Check the frame(frame like object?) and the bottom corners of the cab closeout for rust.
As stated above, the 4wd conversion is pretty common. Same process as for an XJ. If you want to go whole hog, get a '99 XJ that has been smacked in the rear for your conversion, and while you're turning wrenches, swap the front clip and interior.
(Late model MJ conversions are sweet!)

I would crawl underneath as well and check out for rust. Mine didn't have any thanks to all the oil leaks coating everything.

Just did this on mine, as said its not a hard swap and definately depends if its auto or manual. Also depends what your putting in for a 4wd trans. Theres plenty of info out there and on naxja about doing the swap. Pretty much did the entire thing on my own. Swapped BA10 for a AX15 and 231, both axles and lift yada yada. A tranny jack is a good piece to have to move the trans as well as axles and stuff around the garage. Couldnt have done it alone without one.

I did 4 swaps so far and about to start another (with an AMC V8) Pretty simple swap if like to like. Last one I did was 5 speed to auto and 6" lift at the same time.