Is it a bad window motor?

Or is the window motor's plastic gear stripped? (D0AZ-62234A24-B.. Gear Kit)

It could also be a broken plastic window roller.

On the end of the regulator arm is a plastic window roller. The movable stud of the roller bolts to the arm, the plastic roller fits into the window channel that bolts to the glass. The stud breaks off from the roller, causing the window to either bind in the door, or fall down into the bottom of the door.