window troubles (126)

[JustinMorrison]

About a week ago my drivers side front window developed a problem. The window goes down just fine, however when raising the window, just as it approaches the fully closed position a very loud "thump" is heard repeatedly until the button is released. I finally got around to removing the door panel today and got to looking around. First, I found a small black plastic "nut" lying inside the door. I'm not sure if it's related, but it's there. Next I saw a small white plastic piece which is attached to the window motor which had been ripped. Finally, when raising the window I can see that the motor itself "turns" counterclockwise until right before the window is all the way up, at which time it "thumps" back and forth until the button is released. I have enclosed some pics, and if any others are needed to help, let me know. In case anyone was going to ask, the tape on the motor has been there since bought the car. This is a 1987 560SEL, by the way. Thanks for any help!