Doing an automatic conversion on my 91YJ. Cannot seem to get a more than 1 agreement on this. Almost had 2 to agree on an ‘89-‘93 would work. I do have a lead on a good priced 2000, but was told that is too new. At this point if I could get 2 or 3 agreements on years I would run with it, thanks.

 

Any of them will bolt to a 4.0 and you will also need an aftermarket controller to run one so the only real concern is that it has the correct spline count on the output shaft. Your 91 NP231 transfer case should have a 23 spline input, so any 91+ AW4 should work.