Originally Posted by CentralCoaster

Is it the transmission? Remove the spur and bent and see if the trans rotates freely. The case is a tight fit and it can work in your hands but bind up after you tighten the screws and motor plate down. If that is the case back them off a bit and just snug them (with locktite on ones going into motor plate)

Mine has loosened up nicely since, but you don't want all that heat/friction.