Anyone ever get a definite solution for this? I believe my truck has the same squeak :-(

I think I had another thread for this as well where I indicated that it was rear u-joint. It was squeaking for a long while and then it suddenly stopped. I guess at that point some of the needle bearings had disintegrated because I had minor drivetrain vibration during acceleration after that.

Anyways if the symptoms from your truck are the same as here then I'd say there is a good chance that it is your U-joint.

~D