The truck in question is an '08 with 3.73 in the diff. I'm running the minimax with the hotdamn and race-shift tunes. Why would the TC lock-up in fourth gear under a heavy load,unlock shift into fifth and lock-up again, is this normal ? I have installed procomp ladder bars for the 6'' lift the truck has and its on 37's. Also what can ido for the limited slip only one spins it sucks? Thanks in advance for any help guys.