It is a dealership part, so the only way to get it is from the dealer, or a used piece. If you do a search, you will find that is a common problem on these cars. I am on my second moonroof motor/gear myself. There probably is no way to get just the plastic gear. People have tried with no luck. My b-in-law even works for Webasto in Pontiac, and the factory can't sell the gear itself as Ford owns the rights to it.
