I know I've mentioned this at least 6 times, but it is the forward motion that will spin the Bendix out of engagement. It's just the same as when the starter makes the engine fire up, then the engine speed is faster than the starter pinion, and it spins the pinion to the rear, just as Ron also said.
If you are still in doubt, just look at the direction of the helix and study which direction the starter pinion must turn to make it move rearward out of engagement. BTW, notice I didn't say moving the car rearward won't unstick the pinion, as either direction might unstick the gear teeth, but it is the forward motion that spins it out of engagement.
I will not sleep until everyone is a believer!
