I just went through this same type deal. Replaced the tranns, replaced the TCU, had the tranny replaced under warranty. It was a bad u-joint in the rear drive line in the end. Hard to see so it's hard to inspect. Putting the fuse in puts 12v to the transfer clutch so it makes you think that the transfer clutch is bad because the sypmton goes away when there is actually just a bad end on the drive line. Relatively cheap fix compared to everything else I paid for.