So it's still not going? Maybe it's in your diff? I took mine apart to put in the bearing upgrades. It's not too bad to tear down and check your gears in there. Also check the c-clip on the opposite side of the spur gear. It goes thru the case and is fastened on the other side. Careful, it seems to me that the c-clip is kind of an odd-ball size, and tough to find outside of a hobby shop.