OK, ive got a 99 LS, and when i drive it theres a sort of thud-thud thud rumble coming from the rear, the faster you go, the faster the thud goes, until its just a rumble. Ive coasted down a hill with the using the clutch, and i could still here the rumble, so were almost positive its coming from the rear tire i think it might be a problem with the tire, but im not sure and was wondering if you guys would have any insight or advice as too what the problem might be.

 

I think you are right. If it gets faster as you go faster, is has to be something with the wheel/tire or maybe the brakes. I'd just take the wheel off and see whats up.

 

Or maybe a wheel bearing.

 

Is one of your lug nuts loose??

 

Exhaust or muffler touching underbody?

 

no, im pretty sure it has something to do with the wheel/wheel assembly. Im thinking about jacking it up and maybe spinning the rear tires somehow to isolate the noise