1980 300CD window issues
 

My front passenger window will not close right. it goes up all the way then falls down 1/2 to 1 inch. If it does close all the way and you slam the door the window falls an inch. Does this sound like a bad regulator? i took the panel off but can't find anything obviously wrong. Window motor sounds healthy. Closing the window right at the top of its travel it bounces and falls down an inch ( best way i can describe it).

thanks for the input.

When you had the panel off did you drive around like that for a while, operating the window?
My PO had an issue with the drivers side (before my time) where the evidence of a brazed repair was clear after I took off the panel - one of the regulator mounting bolts worked the mounting hole larger and everything would move about when the window peaked and then the next time would not go up high enough to close.
I've ahem had a piece of hardwood stuffed in the door to make the regulator stay in the right location for several years.

No I have not driven with it off because the car is not registered. It will not close all the way as it bounces when almost up and falls down. I found some interesting things inside the door to. I found some fuel line and a screw driver and some broken plastic prices. It almost sounds like the motor gear skips on the regulator. I can make a video if that would help?

Did you lower the window to see if the bolts that holds the window to the window mechanism are tight.
My drivers window was going slow for months It finally fell apart. My repair story is here:
front window problem