The rear seat belt holders on the sides of my crew cab rattle intensely from my subs. Also, the panel under my rear glass, and of course, ANYTHING that happens to have been left in the door pockets by my children. The over head storage does it as well, and the dash where it meets the windshield, just to each side of the center defrost vent. I've also got some under the dash rattles(pro'ly vent ducting). Yes, I know, time for some deadening, but that will come when I have the money for the rest of what I want.......