Sorry I posted this t case question in the wrong section.... Yeah I am a noob

So I have a 93 XJ and the 231J t case went out, my friend was parting out his 91 XJ with a 242J t case in it. So I figured the t case swap would work just fine.... I cannot get the darn thing to marry to the transmission. It seems there is a metal ring inside the 242 t case that is not allowing the shaft from the tranny to go all the way in. So I am left with a quarter to half inch gap and she wont go any farther. I put the old one in and she almost fell in. So I am assuming this is the issue. I will post pics when I get a moment but I am all dirty still. Oh and by the way the trannys are the same also. Any ideas? anything would help at this point...

First, check that the spline counts on the two transfer cases is the same. If its an automatic trans, you may find the 91 is a 21-spline and the 93 is a 23-spline. Also check the length of the snout and the depth of the splines as that may be different.

http://www.novak-adapt.com/knowledge/np_nvg_input_gears.htm and http://www.drivetrain.com/parts_catalog/transfer_case_replacements_and_parts/jeep.html imply that the input shaft lengths should be the same. If you end up having to swap the input shafts on the xfer case, this might be helpful http://www.hobbyguild.com/jeep/index.html