ill try to explain this the best i can. there is some type of clunking popping noise coming from the back of my truck.. its like where the drums are on the rear.. the wheels are tight.. but its very aggrivating.. i thought it may be loose u- bolts since i put a bigger block in the rear.. but i dont think thats it..also sound like it could be coming from the leaf springs.. it does it alot when i am kinda flexing into a driveway or backing up just like a clunk clunk pretty noisy or if im on a bumpy dirt road or something.. it doesnt do it just driving slowly forward it only seems like it does it when flexing like i said or bumpy road.. Also when i push on the bed from side to side it sounds like the clunk comes from those drums but when in the truck sounds like it comes from right under the back seat