"Clunking" window

The passenger side power window is making a clunking sound everytime it goes up or down. I took off the door panel and didn't notice anything loose or off track. The noise seems to be comming from somewhere near the window motor. I was thinking that it may have something to do with the part of the window regulator with the teeth on it? I really am confused by this whole thing, and any help would be appreciated. Thanks.

Nobody knows?

Could the window regulator be damaged? If the regulator is slightly bent would it make a difference? Anybody have any ideas?

Only thing I can think of is maybe the rear roller on the track has come loose.. Mine popped off and the window would clunk going up and down.

If the rollers are flat spotted or worn, if the regulator arms are bent, if the motor mount rivets are loose, if the gear is loose or bent or teeth are broken, if the tracks are loose, if the stops are loose, they can all cause a clunk.
Run it up and down with the panel off, it should become obvious.

Thanks guys. I checked the screws on the window motor (it isn't the original motor) and they are still really tight. I'll check the rollers for sure. Hopefully I can come up with something. Thanks again.

I'm bringing this back up because I finally got the problem fixed. It was the window motor that was the problem. The gear on the motor had a lot of play in it and apparently it was causing the window to clunk when it moved. So my advice is to stay away from the $20 ebay window motors.