I have the pinion drive gear out of the gearbox and it seems to be in good order with no splits on the cogs. However I notice the cog spins freely on the shaft and it seemed to me that the cog should be locked to the shaft in order to transmit power the remaining gears in the gearbox. The problem I am trying to fix is the motor running does not turn the planetary gears with any strength. They might start to turn a bit and then stall and don't turn.