on the top of the rear shocks is a shock mount plate made of rubber with a built in heavy steel washer for the top of the shock. when they tear the shock moves up and down and actually can hit against the car at the top, you do not have to remove the shocks to replace it. remove the access plates and bounce the car while you watch the mounts. youll know if this is your problem,the part # is 9461524, about $25 bucks each from volvo.