This is the nylon wheel that is driven by the electric window lift motor. 1987 TO 1998 from VIN 20004 onward

Window Motor plastic coupling that goes between the pin on the window motor and the worm shaft gear inside the gearbox. From 1978 VIN 36500 approx until 1987  

This is the plastic coupling between the window lift motor and the gear box.  1981-1998 From VIN 1001 onwards