Transfer case swap

Just a quick question after searching through 15 pages and not finding quite what I wanted:

My 89 XJ's NP242 is popping like crazy now in 4wd, especially when it's in reverse. I messed with the linkage but it's not really getting any better so I'm ready to swap in a NP231 as soon as possible.

I'm pretty sure that all 87-90 XJ's had 21 spline inputs on the transfercases but I'm looking for a second opinion. Given that the input splines are the same, is it a direct bolt in? What else off the donor will I need? Will I need the shift linkage? I heard someone mention that the shift gate is different but shouldn't it still fit?

Did you see this one? It looks like it should be pretty easy:
http://www.naxja.org/forum/showthread.php?t=18365&highlight=np242+to+np231+swap
Just a few parts and you should be ready to go.

I saw a few threads, but they all varied in saying how difficult it was. Some said that it bolted right in, some said that you need a new linkage, gate, and bezel.

I'm going to try and find one out of a Renix, Automatic XJ. If so, I think it'll all swap right in if I just cap the vacuum lines.

Still need to know about the linkage though, and for sure how to hook up the 4wd indicator lights.

good reading on the 231 -
http://www.novak-adapt.com/catalog/model_231_parts.htm

http://www.opiebennett.com/images/Jeep/D4-ford9-swap/Day 15/np231.htm

the 4wd lights on the 231 have a detent ball style thingy that screws into the cases and "senses" the shift fork location...

RyleyF said:

I saw a few threads, but they all varied in saying how difficult it was. Some said that it bolted right in, some said that you need a new linkage, gate, and bezel.

I'm going to try and find one out of a Renix, Automatic XJ. If so, I think it'll all swap right in if I just cap the vacuum lines.

Still need to know about the linkage though, and for sure how to hook up the 4wd indicator lights.

Click to expand...

We Just did this. I have a 2000 that had the 242. I bought an '89 XJ that had a 231 w/th SYE done already and the input shaft changed to 23 spline (Previous owner swapped in a 98 trans, hence the 23 spline). We swapped the 231 from the '89 into my 2000, and then put the 242 into the '89. The actual removal and bolt-up on both of them was identicle and pretty easy. Just make sure you have a jack and someone to hold the case as you slide it back. It kind of amazed me how easily the case slid right off the transmission. The exhaust can make it a pain depending on your setup. We actually had to remove the upper exhaust bolts where the manifold connects to the down pipe to move it out of the way. Other than that, we had no other problems.


The linkage from the 2 cases were different. If I remember right, the linkage on the 231 was shorter than on my 242. So we had to use the piece from the 231 on my 2000. If you play with it enough, I'm sure either would work though. The shift bezel's are different, but that's just a cosmetic thing. I know which position I'm in so it does not matter to me. The older 231 we swapped in did not have the same kind of connector for the indicator lights, it was actually in 2 totally different spots, so I just do without. There are ways to make them work, but I'm not toally sure whats involved on the older jeeps. Hope this helps...

Just did this swap in my '89. I used a 231 out of an '02 Yj 4cyl, which is still 21 spline. You need to swap the linkage and the bezel. The bezel is not a cosmetic's thing. The movement of the tranfercase shift lever is completley different in the 242 vs the 231. It's a really straight forward swap.

The movement is different, but the 2000 shift gate and bezel for the 242 allows for proper shifting movement without swapping them. I am not sure about the earlier models. We have yet to finish up the '89 we were working on to get the linkage dialed in all the way.

Will I have a problem with the vacuum system on an 80's 231? Since my 242 has no vaccuum disconnects, do I just cap off the hoses on the 231? I'm going to be pulling one out a Renix so that they both have the same input shafts.

I also have heard that if you just put the electronic shift light sensor in half-way to the 231's shift light sensory-hole-thingy that it'll work. Any further and it'll jam it up. Any credibility to this?

Did a 95 242 to a 241OR,nothing but the Bezel!

It's definitely toast. Today I had to pull some kid out of a pond (dumb kid just got his license today) and it was poppin like hell in forwards and reverse. My rear tires went into some loose dirt while i was in 4HI, and no power was going to the front wheels, I just had one rear spinning, meanwhile the popping continued.

I took off the front driveshaft today, and it sounds like the chain's hitting the case when I turn the front output, and I can actually hear the chain hitting the case when coasting at about 35. Can't wait to get rid of this POS and get a 231.

By the way, what would you guys say is too many miles for a 231 to have? I'm going to be pulling one from a junkyard and want to know that the 231's chain wont' stretch in a week either. Do they have as much of a prob with chain stretching as the two-fourty-poop?

RyleyF said:

It's definitely toast. Today I had to pull some kid out of a pond (dumb kid just got his license today) and it was poppin like hell in forwards and reverse. My rear tires went into some loose dirt while i was in 4HI, and no power was going to the front wheels, I just had one rear spinning, meanwhile the popping continued.

I took off the front driveshaft today, and it sounds like the chain's hitting the case when I turn the front output, and I can actually hear the chain hitting the case when coasting at about 35. Can't wait to get rid of this POS and get a 231.

By the way, what would you guys say is too many miles for a 231 to have? I'm going to be pulling one from a junkyard and want to know that the 231's chain wont' stretch in a week either. Do they have as much of a prob with chain stretching as the two-fourty-poop?

Click to expand...

I personally haven't ever had that problem and haven't read many threads here about it, so I'd guess you'll be less likely with the NP231.

What's the best way to go about swapping out the shift gates on the two different t-cases?