HELP!!!! 91 NP231 tranfer case swap into a 2000 automatic with NP231

As the title says I am trying to figure what all is needed to swap a NP-231 transfer case into a 2000 Cherokee with an automatic and NP-231?

The 91 np-231 is from a 4.0l with ax-15 trans.

The 2000 is an automatic with np-231.

I have searched and found that some have said the spline count is different between the two. I have also found that some are saying that all the t-cases with an ax-15 behind them have a 23 spline output. I would assume that the 2000 with auto would have a 23 spline output as well?

My good friend has the 2000 with a bad t-case and I have the 91 np-231 sitting around and was going to let him use that. I just want to know if he has to swap parts over. I know that the tailshafts are different, could we just swap the 2000 tailshaft assembly into the 91 t-case? Any help or info would be greatly appreciated, we are planning on doing the switch-a-roo this weekend.

Not sure if you can swap the tailshaft assembly, might be able to, might have to swap part of the housing and/or tailcone as well, haven't looked into it.

If you swap in a rear driveshaft for a 91 with an automatic (and the same rearend as his 2000 has), you should be fine. The rear driveshafts for the 95-down and 96-up are different in length by several inches and have slightly different yoke designs... don't ask how I learned this!

You may have to swap the VSS, I am not sure if that changed for the OBD II years. The spline counts you mention are the transmission output shaft spline counts, and they will match, 91 and later are all 23 spline.