Interesting... Tractors have a big lever or button that locks the differential, none on the fun factor! So locking the diff, from what I gather, involves putting some extra thick lube in it, or a mechanical method of locking the two half shafts? Would the extra thick "gunk" not cause the whole thing to get hot, and load the engine unnecessarily, and eventually ruin the gears?? My diff has some method of limiting the slip, not sure what as it was RTR, but my assumption is that it is some very viscous grease...