You've had one I've never seen. I've seen too tight but never too loose. The auto hub is so thick that I have to actually force the motor away from the gear and tighten it or it is meshed to tight. With wear, I'll have to re-position the motor or I will end up with too loose.
ORIGINAL: Oracus
It was too loose. For awile I thought my MH main gear was out of round but it turned out to be gear mesh too loose.