i am sure more than a few of you have experienced this: after the power window reaches its topmost position it goes thump, thump, thump,thump, thump as long as the button is held down. i have experienced this on my aunts 91 560 sel as well as my 300d so i know there is something fundimentally wrong in the gnarly MB window regulator design. can any identify what this noise is and how to rectify it? i suspect the stop pad but i could be wrong!