I just discovered that one of the motor shaft couplers has come off. I believe I now need to replace the motor. However the parts store says the GP 40 motors are out of stock and / or discontinued. I wonder if it possible to solder the coupler back on to the motor shaft? Otherwise I am open to suggestions. Hate to lose the engine. it cost $35 to purchase a new under chassis. Just noticed that the chassis are out of stock. Almost the cost of a new GP 40 diesel. I hope I am making myself clear as to which part is broken. It holds the plastic propeller shaft that connects to the trucks.