I replaced my bulkheads with billet units. when I got the e-Revo brushless back together, the front wheels turn one direction and the rear the other direction. any help where I went wrong here? don't the diffs install in one direction only in each bulkhead? and wouldn't they turn in both directions to allow for the reverse gearing? It just locks up when trying to manual roll it. Lord help me if I hook my Lipos up to it and hit the throttle if the front wheels are working against the rear wheels. Help on this is greatly appreciated.