This all started a few months ago when it looked like my driver's window wasn't closing all the way and making wind noise. It looked like there was a tiny gap at the top rear corner. I could usually stop the noise by momentarily hitting the button "down", but it wouldn't last. It looks like the window just isn't going up straight anymore and leaving a tiny gap at the back corner.

A few weeks ago I removed the door panel to see if I could see anything wrong, but I didn't so I lubed all the pivot points and the sector gear. After that I noticed the mechanism would make a loud "snap" when it reached the top and the sector gear would flex sideways against the door reinforcement bar. Now, it doesn't just make one "snap", but a loud "ratcheting" noise if I don't let go of the button as soon as it reaches the top.

So, what do I do that's easy to fix this? What is there that's supposed to stop the motor when the window reaches the top?
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1992 745 approaching 500k km