[FrankJ]

Last year we had a FP on our arm. We could get the FP motor smoking hot with no stutter. We were using a jag & a big breaker. We eventual limited the output command to the jag to keep the current to a reasonable level, but that is a different story. Maybe it is the self resetting circuit breaker doing its thing?

Different years gear boxes come with different tooth pinions. It might be that you managed to get a smaller pinion installed. It will work on low load, but skip on high load.

The FP gear box is used on an electric kiddie car. It will run forward & backward. They are as close to indestructible as anything in First.