Transmission cleaning and maintenance is important for any RC vehicle, including your SC10. For those of you who bought an RTR, you may have never opened up the transmission, and if you neglect it for too long, it will not perform the way you want it to. Transmission maintenance includes cleaning, inspecting, and lubricating the gears and bearings.
This maintenance should be performed routinely about every 5 to 6 runs or every couple months if the truck has been sitting around for an extended period of time. Also, anytime the transmission does not feel smooth or unusual noises can be heard, the transmission needs to be inspected.
First, you need to remove the transmission. It is not the most difficult thing to take apart so use your manual and start unscrewing. Be sure to keep track of every part and screw. There is nothing unusually tricky about this and learning the hard way by figuring it out on your own is the best way to do it (see Taking apart and Rebuilding your SC10).
After you have the transmission out, open it up. The first thing you want to do is inspect all of your gears and bearings. Open the gear differential and make sure nothing is damaged. Next, check that the bearings' casing should be intact and all of the gears should be meshing smoothly. If any of your gears or bearings are damaged, you need to replace them.
Next, you should clean your bearings and gears. Nothing should be too dirty, but cleaning everything is a good way to keep everything smooth. Clean the bearings by soaking them in a small cup of WD-40. The gears can be sprayed with WD-40 as well and then washed in soap and water. The gears inside the differential do not need to be cleaned if everything seems to be working properly and there is no dirt inside.
Now for lubrication. Add some black grease to the gears inside the differential and it should be good to go (it needs to be nearly filled). We recommend putting some differential fluid (5000wt-7000w) into the gear diff instead of the grease. The black grease works well for most people, but the diff fluid offers tuning capabilities (by using different weights) and tighter diff action which many racers prefer. For the gears outside of the differential (idler and top shaft), add a small dab of grease to top gear (the only metal gear in the transmission) and rotate the top gear to spread the grease around.
Make sure everything is meshing properly, throw your bearings back into the slots, and you should be ready to reassemble the transmission.
Now your transmission should be running smooth which will make your car faster and your motor work more efficiently. Remember to perform this maintenance regularly, every 5 runs is ideal but at least every 10 runs. Neglecting this kind of maintenance will cause your SC10 to run poorly and a transmission rebuild will be in your future.
See our post on Differential Options for your SC10 if you are thinking about replacing the gear differential with a ball differential.