I did the 4wd swap on my 87 MJ with a tranny and T-case from an 89 XJ...... drives perfect shifts perfect.... but runs like crap/stalls out when shifted into Reverse.. if i get some higher RPMS going it will run fine but if i let it idle it will either run like crap and then stall or it will just stall out..... not sure what to go for first???