I have a 2000 xj aw4 np242 this transfer case has the 23 spline input shaft (I believe)
I have a np231 from 1990 I wanted to swap in. I think this has a 21 spline input shaft.
My question is, can I take these cases apart and swap the input shafts over or would I need to buy a new input shaft for the 231?
Also would this swap even work?

 

I dont know, but just out of curiosity, I cant help asking why? (unless your 242 needs rebuilding)

You are swapping older parts in, you will have to rebuild it, a lot of work, time and $, you lose Full Time 4wd (a feature I like)

The 242 is not weak either

sorry, I know dudes usually hate on doubters

 

I'm with awg on this one.

 

Count the splines on the 231. It could be 23 or 21 depending on whether it was behind an auto or manual, and 1990 was also a transition year. More than likely the input shafts are not interchangeable as the bearing width and gear cut changed at some point. For reference -> https://www.novak-adapt.com/knowledg...vg-input-gears

I wouldn't put a 33 year old xfer case in without rebuilding it, unless I was flat broke and desperate. I'd rather rebuild the 242. Check and replace driveshaft u-joints while you got it all apart.

Edit - Also want to point out that 231 won't have the spot to screw in the 4wd indication switch.

 

I’m honestly not entirely sure if my t case is bad, I just am hesitant to spend a bunch of money to fix it and it not be the problem.
Problem being: When I have my front driveshaft installed I’ll get a noise from the case that sounds like the chain is dragging on the inside. Once I engage 4wd (part time full time or 4L) I’ll get a loud clunking noise even when just rolling forward, it sounds like something is binding inside. If I roll up to a hill and put any load on the front wheels the noise will get much worse.

 

Sounds like a badly stretched chain to me. If you change the oil, is it full of aluminum shavings? What are your mechanic skills like? Rebuilding the case isn't difficult, just need basic tools and some attention to details. There are plenty of youtubes out there.

 

I changed it before it got real bad and it was a bit shiny. I didn’t notice any huge chunks of metal though.
what would be a good rebuild kit for this model tcase with a new chain?
2000 XJ classic 4.0 aw4/242

 

I'm actually looking to rebuild a 242 myself to stick in my MJ, so I'm eager to see what kits other recommend.

 

You can't use a 231 on dry pavement it needs to be slippery or you will break the chain or u joints.

 

We seem to be losing the thread here a bit but, fwiw, my take on this is while OP's fiddling about swapping bits over, he might as well just rebuild the 242. (of course some folk prefer the 231 -but he doesn't suggest that.

 

I agree with that to just rebuilt. I have the 231 and wish I had the 242 but am 70YO and just can't lay on my back that long anymore lol
Dave

 

One way is just to buy a spare 242.

Make sure it fits your year

I got one for $A125, and also offered a bloke $30 for one "that needed rebuilding"...I was going to use that one to learn and for spare parts.

He felt insulted and declined

 

If only. When the one in my '97 self-destructed, I replaced it with the one from my parts '96 but I wasn't as clever as I thought I was when it came to the different switches & when I actually needed 4WD there was a bang - & I had nothing, not even Park. Backing off the 4WD switch seemed to release some tension & then it worked but, somehow, it's effectively a 231. The XJ's now running on the TC from the '99 (which is awaiting a trans.) but time will come when it needs to go back - then what do I do, live with the "231" or try to make one working 242 out of the 2? Why, because TC's are like hen's teeth & cost, probably, £3-400, I've not looked lately.