Johnny's Grand Hauler

[mavrick0]

You will probably find them on eBay quicker the waiting for RC4WD. But if you don't care about unlocking the diff just take on of the planetary gears and remove it from the shaft and then reinstall in up against another planetary gear and that will lock the diff. The other way is to get the Tamiya reinforced gear set which they've been nice enough to include a set screw hole in the diff casing so you can lock the axle that way.