Sorry if this has already been answered, but I'm new and I need help. I have a '96 v-6 with a 5-speed. The car is making a hollow, mechanical rattling sound. Imagine the sound of a muffler rattling against the underside, or of the mini spare/jack rattling in it's well. It's not either of these, and no one that's looked at it can figure it out. It only happens while coasting down (no gas, no brakes,) and applying the brakes has no effect. Anyone have any ideas? (The sound is coming from the right rear, outside of the car.) Thanks...