This should be the last job I do on this van, I was just wrapping up another repair and found that my passenger side front window wouldn't move. You could hear the motor spinning but no joy. You could grab the window from either sides and push it down but it would pop back up!

Did some snooping around on YouTube and it ended up being this thing:
https://www.dormanproducts.com/p-10549-747-411.aspx

There is a plastic gear that meshes between the regulator gear and the motor worm drive. The plastic rollers disintegrate eventually but there's a giant spring to hold the window up.


My 1991 had the regulators held in with Torx head screws instead of rivets. I found you have to separate the motor from the big gear if you hold the window up instead of following the service manual instructions which recommend removing the front vent window & frame. It's unclear to me how to get the motor back onto the big assembly after it's repaired but I guess I'll figure that out when I go to reinstall it next weekend.

Replacing the motors should be a last resort

 

Fixed up the van today. I would recommend taking a photo of the spring in case it falls off the window regulator. This is not a job I would have made money on but it certainly saved me money.

 

Good information!

 

GM used the same style system for the headlight motors on various vehicles. With the same results. And the same fix.