1984 c4 headlight gears
#2
5th Gear
I had a motor go bad on me not too long ago. I would highly recommend upgrading to a metal gear assembly, they're just more durable than the plastic set the cars left the factory with IMO. You can find ones with aluminum gears for around $50. Any grease that won't damage plastic components should work just fine.
#3
I would highly recommend not using the metal gears better to have the cheap gear go than the expensive motor. The pucks on mine went gears were still good.