I would go back to basics. Double check underneath for any visible leaks or breaks on driveline and tranny/t-case areas. Then start it up, make sure your clutch is working correctly with all the linkage engaged and disengaged. Next I would try to shift thru the gears with the t-case in neutral. then try with the t-case engaged in all. Go thru the fundamentals and try to eliminate any of the problematic areas and post back.
85' CJ7 Laredo, 383 GM, Turbo 350, NP 203. SOA, 2" frame lift, 34" TSL swampers, Dana 30 open, AMC 20 w/ detroit locker, 4:10's, 1 Piece Mosers, 35" boggers to abuse when needed.