Noise Driving me Crazy

Guys I need help with this . My 99 Silverado is make a squeaking noise coming the middle of the truck .I have eliminated brakes and u-joints from list of possible causes. The truck only make noise in reverse but in drive it does fine. Check all fluids and they are fine also. checked my torsion bars and the bushings looking dryrotted. Is this the cause of the noise. Any help I can get will be appreciated.

You said you ruled out ujoints. Did you do this by replacing them or by just getting under the truck and shaking the shaft?If you did not replace them or atleast removed and inspected them, then i suggest you take a closer look, because these newer trucks have been having a prob of the original ujoints (factory) seezing, Mine sounded like a old red wagon, squeaking, vibrating at highway speeds, and shaking or taking a crow bar to the ujoints did not show the prob. After finally taking it to dealer thinking it was my rear axil they took out the factory joints which were solid, ungreasable, and completly seezed and destroyedwith rust and broken needle barings. This was at 40,000 miles on a 2000 silvy...JJ