Ive been for weeks now trying to find a rattle that has me stumped. I put new Bilstien shocks on the rear and now i have a rattle. sounds like metal on metal to the point it sounds like the bed is about to fall off. I only hear it at slow speeds under 25mph, anything over that road noise blends it away. I have 30,000 miles on the truck, rear diff hasnt been changed yet could that be it? Also have newer rims and tires had them on now for 1 year. any ideas would greatly be appreciated...