I replaced all the gears in my gearbox last night. I had the idea at work to seal off the gear box and to put oil in it for lubrication to keep the heat down. I sealed it all the way around then drilled a hole in the side to use a traxxas slipper clutch plug to plug it up. I added enough 90 wt silicone shock oil to put just a small amount in the bottom of the case. I figure its not enough to reach the bearings and leak out, but enough to thoroughly lube the gears. Its raining out now though, cant try it till at least tomorrow.