Popping/Thumping noise when towing 5th Wheel

[danmcguire]

When I am pulling my 10000# 5th wheel, and I make a hard left turn from a dead stop, as I accelerate, I heard a popping or thumping noise coming from my right side of my '97 2500 diesel 2wd truck (106,000 mi) It is not a metallic schreeching noise, but a thump/thump noise. It goes away as soon as I straighten up and it nevers occurs while turning right and it nevers happens if I am just turning sharply to the left as long as I am moving before I begin my turn. Only happens when I come to a stop, then have to turn left sharply and accelerate to get going again. What's happening? Is this my rear axle, U joints, axle joints, etc? I have had the front bearings repacked, but never the rear's other than draining/refiling the rear end. HELP!

 

[B.G. Smith]

Noise

I would check the right side of the hitch and rails for loose mounting bolts/pins etc. bg