Hey everybody, I'm a NEWB to the jeep world. I have a 99 4x4 xj with 4.0, auto,np231. It currently has the stock drivetrain with exception of a slip yoke eliminator and welded spiders in the rear diff. 3" lift was installed by previous owner. It's a trail only rig for me, I'm running 35's now which I feel is probably on the limit of what the 8.25 and dana 30 can handle, especially in stock form. I'm a career mechanic and have had squarebody chevy's my whole life that I still work on.

My question is, does anybody know if there is a passenger drop transfer case that I can swap in place of the stock 231 without modifying the transmission and adapter? I have a feeling these axles aren't going to last long and I have several sets of 1 ton axles from my chevy's. Locatiing a transfer case is a far more feasible option for me than finding a driver drop front axle. I only want to axle swap once when these break so I'm pretty set on 1 ton swap.

Any help would be awesome, I've been searching and searching but can't find any answer.

 

There isn't a great answer.

Some older GM and Dodge applications used passenger drop NP231/241/207/208s. The Dodge one should have the right bolt pattern, but you'll likely need to swap the input gear in them, which will require tracking down an early (pre-95) 23 spline input gear. GM stuff seems to be more common to find, and a flip ring likely could make the GM one work, as the mount pattern is inverse, or you could possibly redrill the tcase output. However, these were considered to be 'weak' transfercases that often went to the recycler for the aluminum content rather than being kept around, I went looking for a passenger drop NP241 recently and came up with zero. The 207/208 has a different ratio and is IMHO junk.

You could use a doubler to a GM NP205, like the Northwest Fab Ecobox, if you have a round pattern NP205. They also make a racetrack pattern setup I think, but I have no personal experience with it.

Personally I'd sell the GM axle and buy a Ford D60, or Superduty axles, as it's just a waste of time and effort and you'll be stuck with a low pinion front axle. YMMV.

 

One option I forgot, because I've always personally felt it was a piece of junk, is the D300 (Dana 300) transfer case. It's heavy and weak, and you can spend a ton of money upgrading it to fix that, but lots of people seem to use them.

Also the aftermarket has other options, with the Atlas being the most common and one of the best all around.

 

thanks 2drx4. I had a feeling that was going to be the answer I got, was all i seemed to find through the google but was hoping someone with lots of experience might have found a candidate that isn't commonly known.