RE: Does anyone know how to lock a rear diff?
I don't know what R/C you have, but if it has a gear diff then you can easily lock it by using hot glue on the spider gears (the little gears inside the diff). Then if you don't like it you can just peel the hot glue off. I've done this on a Clod Buster and it held even with all the torque of those big wheels.