[can't stop spinning]

I just picked up my 08 dc 4x4 yesterday morning, and the bed shakes like crazy. The roads where I live suck, and have lots of rough joints/cracks in them. You can see the bed shake everytime you hit a joint. About 1/2 the bumps cause the box to shake the cab of the truck. It's very easy to see the bed still shaking or vibrating even after the bump.

I've never driven another 1/2 ton on these sections of roads before, but I have driven 3/4 and 1 tons, and they all feel a lot more solid, and don't shake like my Tundra. My Dad's 96 Dodge w/ almost 300k on it feels more solid on these joints then my brand new truck. It's rather disappointing after spending 40k on a truck to have this happen.