The Kyosho OT-38 parts bag contains 2 tubes of Silicon Grease as listed in the Lazer ZX manual. It is to be applied on the diff balls.
Silicon grease thins out when hot, so the contact points between balls and rings will not get lubricated (which would cause slipping) while the contact points between balls and their holes in the spur will remain lubricated as they don’t get as hot.
