Rebuilding your ball differential A ball diff requires more maintenance, replacement of diff balls and diff rings. The advantage of a ball differential is that it’s easy to adjust, you just have to loosen the bolt or tighten it. When you setup your ball differential like it should be, your car will handle much better. So maintain your ball differential! What you’ll need: Hex screwdrivers Slipper adjusting tool Rag or paper towel Motor spray Black and silicone grease Brush and/or toothbrush 600grit sandpaper Step 1: Solder the cables of the motor and remove your motor by loosening the screws. Take your differential case out of your car. Remove your slipper. Step 2: Unscrew the motor plate also the screw that holds the casings together and clean the casing of your ball differential. Step 3: Open your differential and take all the gears out the casings. Step 4: Remove the bearings out of the cases, clean the inside of the cases, top shaft and the idler gear with motor spray and let it dry. Take the ball differential apart, clean the balls, rings and outdrives with motor spray and let it dry. Step 5: Place the 2 smallest bearings onto the outdrives. Take your outdrives and add 2 little numbs of silicone grease on the outer side of the outdrives and put the rings on them. You might want to replace the rings if they have a deep groove in them. Tip: If you want a very smooth ball differential, you might want to sand the diff rings. Sand them for 4 secs CW and 4 sec CCW do this 4 minutes. you can place a ring on the female outdrive so it's easier to sand them. Step 6: Add silicone grease on the rings as shown on the picture. Step 7: Put the biggest gear (diff gear) onto the outdrive, doesn’t really matter what outdrive you’ve put it on. Step 8: Drop the diff balls into the diff gear and place them into the slots of the diff gear with a screwdriver. You might want to cover them up with a little bit of grease. Step 9: Take the other outdrive and put it on the diff gear and spin the differential, make sure it’s smooth. Also look what outdrive is the deepest, put the spring (compress it a few times) and the T-nut into the outdrive. Step 10: Take the thrust bolt and put a thrush washer on it. Add some black grease on the washer. Then drop the thrust balls on to the black grease, make sure you don’t loose a ball. Add another ring of black grease and put the other washer on the bolt. And sandwich the balls. Tighten the whole ball differential with the bolt. Step 11: To adjust the ball differential, take 2 screwdrivers and put the into the slots of the outdrives let the rest on a table. Now try to spin the gear. If you are able to spin the gear, you have to tighten the thrust bolt. If you aren’t able to spin the gear, try to loose the bolt. If you find the right setup for you ball differential, put it back into the cases and put you differential back into your car. Make sure you put the bolt at the side of the slipper! Now you have to break in your differential. Hold one tire in your hand and apply 10-20% of throttle, the other tires will spin. Do this for 20seconds and do the same thing with the other side. Now your ball differential is ready to be raced!