[hobbsdog]

Thanks for posting the info. I do believe that is what is happening to my truck to cause the noise. This is my second GMC, my first 2002 Sierra had a major malfunction of the electrical systemand the air bag deployed in my driveway one morning when i started it. Gmc never took responsibility for this default; happened more than once. I sold that truck to get out and bought this 2004 hoping that i would have no problems; now i wish i had bought toyota or nissan.

thanks again