When hitting a pot hole (here and there) I hear quite a rattle coming from both sides of the rear end of my 98 S70. It sounds like - if you were to put a few washers on a nut and bolt, leave them lose, then shake the contraption up and down. I have heard this may have something to do with the sway bar? It is driving me nuts and I am concerned something is about to fall off. The volvo dealer tightened up some heat shield ($50) and told me it was fixed. It is not....