Thanks for getting back. I have some videos if it helps at all.
First one is with the original motor, the second is with the replacement (still used) motor. The new motor isn't as bad as the first and it doesn't make that horrible screeching noise but under load it does the same cogging like symptoms. When the motor does drive the truck it never really gives that jump I feel it should.
Original Motor
you tube.com/watch?v=e0oO2gbEizU&context=C38aaa22ADOEgsToPDskJ3 DojkGUB9dd0A1TUBmoKJ
Replacement
you tube.com/watch?v=rD-lbBMsrDk&context=C30e1e4cADOEgsToPDskKIXN_hrSDiWrm odPuYGpqK
The mesh seems good so I don't think it's that and the car rolls fine without any motor.