The purpose of this article is to give instructions on how to properly build and break in a ball differential and slipper clutch for a Team Associated RC10B4, RC10 T4, and SC10.These instructions will also work for any 1/10th scale ball diff or slipper clutch. I do not claim to be an expert in Rc or claim to know everything about our hobby, but there has been a great deal of confusion about this topic with all of the new racers entering 1/10th scale racing. This article is meant to clear up some of the confusion and make it an easier and more enjoyable process. There are as many different opinions on this topic as there are racers, this is just mine.


Removing the Transmission Case

To get to the diff we must first disassemble the back end of the buggy and the transmission case. Start by removing the two 4/40 size screws that hold the transmission case to the rear brace. Next remove the 4/40 size screws that hold the wing mounts to the rear shock tower, and push the wing mounts up out of the way. Now pop the rear turnbuckles off of the rear brace and let the CVD’s hand freely to the sides of the buggy. You will now need to remove the top and bottom 4/40 size screw that hold the motor guard to the transmission case. Now with a little force the transmission case will pop free. Make sure to remove the motor or unplug the leads from the E.S.C. Set the transmission case on a clean white pit towel, and push the rest of the buggy aside for now.


Disassembling the Transmission Case

Now remove the gear cover from the motor plate be unscrewing the two 4/40 size screws. If you haven’t already, you will want to remove the motor. You will now need to remove the slipper clutch assembly by removing the ¼ size nut and sliding the slipper clutch assembly, along with the spur gear off to the side. Next remove the four, long 4/40 size screws that hold the transmission case to the motor plate. Set the motor plate, wing mounts, and 4/40 size screws aside. The final screw holding the transmission together is the small 4/40 size screw on the bottom, left, corner of the transmission case. Remove this screw and split the transmission halves apart, remove the differential, and set it on your white pit towel, pushing aside the remainder of the transmission case.


The Differential

Disassembling the Diff

Now that we have the diff isolated we can disassemble it. Start by working on a clean pit towel, preferably white so that small parts will be easy to see. Insert a 5/64th size hex driver into the right side of the diff, and unscrew the thrust bolt. Separate the diff into its two halves. Clean all of the parts using motor cleaning spray or de-natured alcohol, once done organize all the parts so they are easy to find.

Next check the diff gear’s teeth for wear and chipped teeth, and replace if necessary. Now take the diff rings out of the outdrives, and feel the diff rings with your fingernail to see if there is a small ridge that the diff balls have created. If there is a small ridge, flip the diff rings over to the smooth un-used side, if both sides have been used it is time to replace the diff rings. Now take some 400 grit sandpaper and sand the diff rings in a circular pattern, until there is no shine or ridge on the diff rings. Most diff rings come too polished and cause the diff to slip because the balls have nothing to grab on to. Many diff rings also have minor imperfections, and are not completely flat. Sanding fixes both of these problems. You need only to sand the side facing the diff balls, however sanding both sides does no harm.


Building the Diff

Now it is time to build the diff. Make sure all the parts are clean and free of debris, grit, and dirt. Start by applying a small amount of Team Associated’s Diff Lube to both sides of the outdrive’s rims, where the diff rings sit. You don’t need to use much Diff Lube, just enough to cover evenly. Now set the diff rings on the outdrives. Apply Diff Lube onto the top of the diff rings, being more generous this time. Now place the diff gear onto the left outdrive[the outdrive with the nipple]. Apply more Diff Lube to the holes in the gear and place the diff balls in the holes. It is important to make sure no debris gets into the diff, so be careful. Now set the outdrives aside and we will look at the thrust bearing assembly.

First find the diff thrust bolt and put it on the end of your 5/64th hex driver. Now slip one of the thrust washers onto the bolt, and apply a generous amount of Team Associated’s Black Grease to the top side of the washer. Next set the six thrust balls onto the top side of the washer, and apply a little more Black Grease on top of these. Slide the second washer on top of the diff balls, then slide the bolt up into the right outdrive[outdrive without nipple].

Now install the diff bearings into the diff by sliding them into the slot on the right outdrive. Apply a little more Diff Lube onto the right outdrive, and slide both outdrives together, and set aside for a moment.

Now find your diff thrust spring and t-nut. Please note that if it is a new diff thrust spring you will need to compress it first, with a pair of pliers. Slide the thrust spring into the left outdrive, followed by the t-nut. Make sure the t-nut is facing the right direction, and has the tabs on the top, not the bottom. Slowly tighten the diff, making sure the t-nut is compressing the thrust spring. Only tighten the diff enough to when you can not move the diff gear while holding both outdrives. DO NOT FULL TIGHTEN THE DIFF, AS THIS CAN CAUSE THE DIFF BALLS TO FLATTEN OUT ON ONE SIDE. Before reassembling the transmission clean out all of the old grease in the transmission gears with motor cleaner spray, and apply a couple of drops of 50wt shock oil to get a quite, smooth transmission. Now reassemble the transmission and the rear end of the buggy by reversing the steps you took in disassembly.