check your spring bushings,
I have a good pop right now because that is a pain to reproduce and after replacing just about everything in the front end I finally figured out that it is the worn bushings in the eyes of the springs. Mine usually shows itself in a turn but not always.
There was a problem with the t-cases in the OBS trucks that I believe carried over to the SD trucks where the lube pump for the t-case would break. The OBS Trucks were 1354 or 1356 transfer cases depending on year.
Here is a good thread on these transfer cases. Maybe someone else can tell you what model t-case is in your truck since I don't know off the top of my head.