Bought a 2000 silverado 10 years ago, and always had this rattle from the rear suspension. If I drive over a bump, pot hole etc. the front wheels no problem but the back wheels I get this rattle, like metal on metal. I've looked under the back and have asked 3 different mechanics to look at it, can't figure it out. All I can only imagine is eather the parking brakes or the leaf springs, what I can tell you is when I drive with the windows down it drives me nuts.