Resolve the binding. May have a bent motor shaft, friction on the gears, side frame bent and touching a drive wheel adding friction. Something from the collision or drop has damaged a truck/motor combination. Side frames bent into the drive wheels is a problem I have seen before that is hard to detect unless you look for it. It acts like a brake is applied to that truck.
John, The motor is not along for the ride. They are the same motor with in tolerance and get the same voltage. So a 5 to 7SMPH difference in starting means a problem. Tolerances are not that great. In the long run one motor will get burned up. G
