Anyone had them strip or no longer make contact with the gear on the motor?

I just installed a new to me motor, tested it before installation and I am getting nothing. When the button is pressed the motor goes for a few seconds and the sunroof glass does not move and I can tell there is no contact to the gears because there is no sound of binding of contact with anything. Just a free spinning motor. I compared the old and new motor gears and there is no difference in diameter and the screw gears don’t look chewed up.

The old motor was definitely making contact because before it went of completely the window would move slightly when the button was pushed.

 

Swap front and rear, that will tell if you if it is the gearbox or the cables.