Truck will not shift into years especially four-wheel-drive

I just had this problem after i changed my tcase, make sure the plate that hooks onto your 4x4 selector is put on, take a good look cause there is a slotted hole it must sit in not just up against, that may have something to do with your problem, hope it helps

Just don't engage the 4WD when you have good traction on all 4 wheels and you'll never have this problem or issue. If you do have it occur, disengage the transfer case. The key is good traction; if you have it on all 4 wheels, are in 4WD and attempt a sharp turn, the steering wheel will "fight you" by jerking back and forth. The front end is on a different turning radius, and the 4WD is locked up trying to keep the wheels turning as if they were on the same radius.