Both. The part that squeaks is the ball joint at the bottom of the shock. Rather than just using the typical hole with a gromet and bolt through it (which allows for 2d motion), MB decided, in its wisdom, that full range of motion joints were needed on the bottoms of the shocks, so they put ball joints on them. Eventually, the balls rust up, as even though there is a rubber boot, water gets in there, and then they squeak. There is no way to grease them to prevent the problem, as the boots are sealed and there is no grease fitting. Any shock that fits this application will eventually develop the problem.