So I recently overhauled my Texas special with a new horizontal motor and e unit and everything was working great until last week when it started hesitating in forward but making a loud skipping noise but running fine in reverse. Sometimes it’s the other way around. I pinpointed the problem with the motor truck itself as I tested the motor  and it is fine. Instead of both axles on the motor truck moving smoothly one axle skips and moves freely with the motor installed. When I take the motor off from the motor truck the gear end of the shaft is pushing up  when I move the motor truck back and forth which is why I think the engine struggles to run in one direction but fine in the other direction. How do I remedy this?