231 or 242 transfercase

[highrollinmopars]

I have a 88 Jeep Xj with a 4.0 ho a auto tranny and a 242 t case. Pending saturday the deal goes through on the 1990 Mj 2.5l 5 speed 2wd I'm getting i will wanting to convert it to the 4.0 out of my xj and also make it 4x4. I'm told i need a different ax15 tranny than the 2wd i have and that I will need to get one from a 4x4. I'm also told that the 242 out of the xj will not work on a ax15 4wd because the spline count is different? Probably old news to some of you guys but can youll shed some light on this to a newbie. I may want to swap my 242 for a 231 should it fit in my jeep. Thanks oh yeah is there anything else I'm not thinking of when doing this swap and conversion? I know wiring will be tricky.