This is about a 2000 gmc sierrra 2500 truck I purchased with 194k a few years ago. It now has 232k. Whenever I go from a complete stop, the noise sounds as if it comes from the rear area. It sort of has a sliding umph noise, as if a slide hammer is going from front to back with a resounding stop as I move forward. I have checked the driveline, the rearend, the bed attaching bolts, and most everything in the rear section for tightness.
I had the bed loaded heavily once and it seemed to not make the noise. When I tow a boat or tow nothing it makes this noise with a sort of bang or stopping sensation at the end like the slide of something that then stops. Who wants to ride under my truck for a diagnosis? ha ha
Like my ol’ friend Wayne Davenport from Alaska says… "don’t worry about it, when the #*@@$%# thing breaks you’ll know what to fix !! " he’s in his 70’s now and very old school and crotchety… so add that into your imaginary voice as you read his quote. He is quite right, so I’m just more curious than worried. He also gave me a running and driving shiny 1964 Plymouth Barracuda once, which I still have… so he’s awesome just to let you guys know!!
I own and maintain a virtual fleet of vehicles, with 4-66 chevelles, 1-1964 barracuda, 1-1969 dodge chinook, 2 chevy trucks of the 1970’s, the gmc pickup, and a 1987 pontiac fiero gt , and a couple motorcycles… not a stranger to fixing things.
Any ideas? Could it be in the transmission? ha, it could be anything we all know that !