Don't forget the shocks as well. I've seen alot of thumping noises coming from the shocks, that get misdiagnosed. If you have more than 75,000 miles on the truck, they need to be checked. Crank on the mounting bolts and give them a squeeze, the bushings can shrink over time allowing them to become slightly loose, causing a clunk. If that does'nt do it, check those spring bushings out real close. Good Luck