I purchased my truck towards the beginning of 2007. The specs are listed in my signature and I currently have 17,000 miles on it. As of recently, I hear (and feel) a loud "thud" noise when going over a heavy bump. I would say that its similar to having something heavy in the bed of the truck that bounces when going over a bump. The problem that I'm not carrying anything. I don't remember the truck making this noise until the end of summer, which makes me think that something is wrong.

The noise appears to be coming from the rear axle. The reason I say this is because when I go over a speed bump, the front suspension goes over smoothly. However, as the rear tires make its way down the speed bump, I hear and feel the thud noise. I may take to the dealership, but thought I'd get some opinions on this board first.

 

I would look at the spare tire, and make sure it is up tight. If it isn't that, yeah I would take it to the dealer to have the rear suspension checked. If you have hauled a lot, that could be it. I have a friend that had a similiar noise and ended up getting new rear suspension from the dealer. His is an 06 Mega. However, there is a lot of experience on this site with weird noises that will reply and might be more helpful.

 

Yeah, I thought it might have been the spare tire too, but it appears to be firmly secure. The weird thing is that I can hear and feel this thud even when towing my 7000lb trailer while going over a bump. I know for a fact that it didn't do this before. At least I'm still under warranty.

 

Sounds bigger but check those ridiculous plastic liners in the rear quarter behind the tires. If loose, could make some noise against the frame, I suppose. Mine were loose. Unfortunate cost cutting measure there.

 

Check your shock mounting bolts

 

Exhaust hook/clamps. On my 06 2500 I had one of the exhuast mounts come out of the rubber bushing and it would make a thud noise against the bushing when i hit a big bump...