Eric it is the gearboxes I just got from you. The motherboard is a 2.4 taigen that came in the tank. It drives one side just fine but not the other. It is something to do with the board or the anti track recoil unit that is on it. It will work just fine as long as the resistance of the volt meter is on the circuit. It was late last night when I was testing and will look into it further after work today. This issue may go back to when I thought I had a gear box issue as the tank was under powered on one side. I'll start with plugging the motors directly in to the control board.
Jimmy