holysbit

Hello everyone!

Im a long time lurker here but had never really had anything to do with jeeps. I had an 04 WJ a few years ago that was bone stock with 260k miles, and I had tons of fun bagging on that, and I was introduced to the community. That jeep is gone but recently I picked up this sweetheart in Colorado. Its a 1990 XJ with the 4.0 I6 and a 5 speed AX15.

Humble beginnings

She is a little rough around the edges but I have some big plans, and I think this jeep is a good candidate. Entirely stock, 250k ish miles but very little rust. There is no rot anywhere except for two points on the body, but everything where it counts is solid and has no rust beyond the surface. That 4.0 is leaking a lot of oil and I can tell it has been for a long time, that probably helped keep it rust free lol. The interior is in fine shape for a 30 year old car, at least everything works except the AC, which my research tells me is basically common law for these jeeps.

My first act is get it driving good, AKA project foundation. For that im putting in a new clutch, replacing front pads and rotors, adjusting the rear drums, and fixing all its numerous leaks (I have a good idea where its all leaking from so ive got gaskets and seals on the way for engine, tranny, tcase, and the rear diff)

My next act is dubbed project liftoff and it involves a rusty’s 4.5” lift kit with a 4 point long arm setup, a Chrysler 8.25 3.55 swap, JB conversions SYE, steering gear brace (ill swap to a dakota box when this fails), ZJ tie rods, 33x10.5 tires, OX locker in the front d30, detroit locker in the 8.25, as well as new ball joints and U-joints all around.

Does anyone have a rig similar to this? Im looking to be able to take it pretty much anywhere, and that would include all but the more challenging rocks

Battle

Nice Jeep and solid plan. We need more pictures!!!

Make sure you do Cruiser's Renix tips (you can find about it here) which will cover some of the known trouble points with the Renix era Jeeps like yours. You should incorporate that into your "project foundation."

My trail rig has followed a somewhat similar path and has had a slightly similar configuration (lowish center of gravity 5sp rig built around skinny 33s). I'd say you may want to reconsider the 3.55 gears. I ran those with 31s and the manual for years and it was a really solid setup. When I switched to 33s, I stepped up to 4.11s first. It was a very nicely balanced combo of on-road smoothness and efficiency, with low-range grunt. I still found myself downshifting to pull grades though.

I've since stepped up again to 4.56s as the Jeep is pretty much a dedicated "long distance trail rig" and the heaviest it's been in a long time (still less than 4500lbs). The torque is awesome - it gets into fifth with ease and can stay in that gear for a lot of driving. Highway cruising RPM is high though - hovering around 3K rpm to keep up with traffic on major interstates.

I get the allure and cheapness of just swapping in a stock automatic 3.55 gear set axles, but since you're going with 33s and lockers, I'd consider 4.10/11s just to give it a bit more torque - especially given you're up in elevation. 4.56s and a stick with 33s is a great combo, but you really have to be okay with high rpm crusining speeds and fuel economy. With 4.11s I could get 19-20 mpg highway. With 4.56s, I get 16-17.

Happy building!