Ok, I don't really know how to describe this but, I've noticed that my 1988 535is with 112,000 miles steering wheel shakes whenever the susension rebounds from a large dip usually in the highway. I've only noticed it at speeds above 50 mph. Kinda like when the car goes up in the air, (the wheels never lose contact), and the suspension has to expand. Anyone ever heard of this or know what I'm trying to say? I do know that my passenger side front shock needs replacing becuase it makes a loud thumping sound when it hits a bump. Is it becuase of that? Or something else? Is it expensive?