RE: BIG CEN MT2 PROBLEM!!!!!
does it happen when you lift up the front of the truck and pull it along on just the rear wheels? does it do it on just the front wheels? If so, it is most likely a bevel gear or ring gear in the Diff. They are very simple to replace, and not that expensive. The front diff is more difficult to take out. so make sure which diff is making noise. Also when you remove the diff you can look through the hole in the bottom of the diff and see if the ring gear teeth are chipped.