White Lithium grease found at ACE Hardware works well, is fine to get within the teeth and bearings and holds better. Also safe for plastic gears and plastics as well.

The Axel grease works better at higher RPM where the viscocity of the grease breaks down a bit, the tank gearboxes do not have enough RPM to turn the Axel grease into a fine lubricant, thus throwing the bulk of it off the gears.