The other day, I had my truck in auto 4wd mode. The roads were mostly snow covered but there were some areas that were just wet. I rolled up to a 4 way stop sign where the road was just wet. I made a right hand turn after stopping and the drive-line binded up so bad, it was almost enough to stop the truck mid-turn!. It felt more like it was in 4wd high rather than auto mode. Made wierd rubbing/groaning noises. It made noise on turns before but never actually binded like that. I bought the truck with about 70k miles and it now has 104K. The drive-line has always been sorta "rough" and noisy but never binded up like that in auto. A couple years ago, I changed the diff and tcase fluids and replaced all the u-joints. Never noticed any excessive amount of metal "paste" on the drain plugs (none in the tcase). Truck "hums" even in 2wd when it's cold outside. Barely hear it in the summer. Auto makes more noise and 4wd high is very noisy in any temperature, especially when accelerating. I had thought the "hum", which seems like its coming from the front, was the wheel bearings, but I replaced both of those when the ABS sensors started acting up, and the sound was unchanged. I'm trying to narrow this down. I think the problem is all in the tcase BUT the humming sound at speed sounds like it's coming from the front. However, I know sounds/vibrations can sorta transmit along one part of the drive-line to another. One thing I do know is coming from the tcase is a ton of play/slop when shifting into reverse. When i put it in 4wd and shift to reverse, the slop is gone. Any tips on narrowing this down is appreciated.