AV,

I have a similar problem on my 190e. I thought I had it licked with a new rear track/tie rod. The boot was riped and that was my best guess as to where the noise was coming from (crawling under the car while the wife jumped up and down on the bumper). There are five joints in the rear suspension and to pin point the source of the noise is difficult if something is not visually obvious. Anyways, after replacement, it was nice and quiet.......for about two weeks. Go figure.

Let me know what you find.

Tinker