Well, I found out one weird thing. One of the motor brushes was put in upside down, the spring to the inside. I found the spring when I took the motor cover off, then while further dismantling the motor I found one of the carbon brushes upside down. I guessing it didn't work very well that way.
On a related note, does anyone know a good place to buy the motor brush screw caps for the potted motors? The one with the upside down brush was in pretty bad shape.