I got the gear boxes apart. Two of the thrust washers were chewed up, so I had to cut down the thickness of some washers I had using my belt sanders and some sacrificed leather gardening gloves. There is slight damage to some gear teeth, but they should still be serviceable. The gear oil looked like Hershey's syrup with how much rust there was in it, but now they ride in pure modern clean syrupy gear oil. Should be good for the next 75 years.
So I bolted everything up and started doing some more systematic electrical connection attempts like this:
Each motor has three wires, Red, Green, and Black.
The red wire connects to one of the commutator brushes.
The green and black wires go elsewhere, but I don't know where.
None of the wires connect to the casing of the motor which I thought was odd.
I hooked up the red wire to positive.
When I hook the green to ground, then the motors turn to open the top.
When I hook the BLACk to ground, then the motors turn to CLOSE the top.
All sounds good. Wondering though, can I use RED as ground and wire the switching to put power to green to open and power to black to close?
It seems weird to hook a red wire up to ground, but I do remember that this car and these motors were originally 6v positive ground. Anybody know if it matters how I do this?