Bought a used 2004 2500HD 4x4 to haul my 5th wheel...
 

Like the truck but is it a bunch bigger then either of my Tahoes. It does make a creak when you get on it and it's more like it's really a big truck and the bed maybe isn't quite as tight as it should be to the cab. I've heard it before out of my past. Maybe in my 84 GMC pickup. It's just a noise behind me and I wish I could put my head around what it is. More of a slight strain. Nothing that seems like it will go away nor ever cause me a problem but I'm hoping a dealer mechanic is listening in. I'm almost betting there is some bolts that could be tightened up to eliminate it. Almost a stress grown from being a big truck.

Thanks... Gary