My transfer case disintegrated on me on the freeway, I think because I later saw my driveline had a fairly large dent in it, probably making it off balance. Anyways, my XJ is a 93, I got a transfer case from a 90. I was wondering if it would swap. Both are NP231. Thanks for your time. I heard that in 1991 the amount of splines on the output shaft from the transmission changed so they may not work together, I was wondering if anybody knew that for sure.

 

Everything you need to know and then some...
http://www.novak-adapt.com/knowledge/np231.htm

 

Thanks man. That's super helpful. Although a little bit confusing as far as the input shaft information is concerned lol.

 

Pretty sure 90 and back are 21 spline and 91 up are 23. Here's the fun part, they came in at least 3 different lengths.

 

Yea, I got that, short and long are commong and the mediums are rare.

 

You should be able to move the input gear from your 1990 case to the 1993 - the 1990 will likely be 21-spline, and the 1993 a 23-spline.

 

It is a total crap shoot as to wether or not they are the right length and have the right bearing collar. Trust me I know. the 90 ax15's are short 23 spline, but a 90 aw4 is a short 21 spline. After 91 it is easier to match up splines, just make sure your trans will accept the input.