need help with electric windows

92 SC electric windows try to go up and down but can't without help.

Electric motors run but windows stick. Glass seems to slide ok so what needs replaced?
Are the regulators bad, or is there a drive gear on the motor that is wore out.
Do I need new motors, or is there a replacement part.

Help appreciated

Can the motors be unbolted with just three bolts, or do the regulators have to come out?

Ok I answered my own question. Took the motor out and disasembled the gear head. Bunch of yellow broken plastic inside the black gear.

So now the question is : are there service parts for the gear head portion? The electric motor itself works fine. Hate to buy a expensive motor for just a plastic part.

part numbers???

I do not know any part numbers, but I am fairly certain other people have replaced these plastic gears. I wonder if a machine shop could recreate them in metal. These electric windows probably use parts similar to the standard Thunderbirds and Cougers, perhaps a junkyard has some in good condition..