The Diffs in the RDX are smooth as glass when built up properly and follow a few simple things. The following steps will ensure you get the silky diffs you are looking for and perform perfectly. The diffs put the power to the ground so we do not recommend skipping any of the steps and make sure the parts are always in top notch condition. Be sure to click on images for close up views. The biggest upgrade we recommend is swapping the stock diff balls for either Carbide (COR1011) or Ceramic (COR1010) balls. It will vastly improve the longevity of your diffs between rebuilds. When assembling the diffs there are 4 beveled washers that are put onto the diff bolt. We recommend a different pattern for placing them onto the bolt. We recommend one face down, then two facing each other, then the fourth washer facing upward. We feel this prevents any possible slanting of the washers on the bolt. Remove the snap ring from the short diff hub. Do not pinch the snap ring closed otherwise it will cause premature fatigue and give you other problems. Pinch it enough to pull it out and no more. After 2 or 3 times of removing the snap ring you will want to go ahead and replace it as it will fatigue. Take out the thrust bearings and clean everything down with motor spray. Check the groove on the diff hub where the snap ring sits for any wear marks or debris. The thrust washers are two different diameters, so be sure to put the smaller one in first. Coat the washer with black grease, insert the thrust bearing, coat the bearing with more black grease. Install the final thrust washer and use the back of an X-acto knife to seat the thrust assembly. Before installing the fresh snap ring, be sure to examine the ring as there is a flat edge side and a more rounded edge. You will want the flat edge side facing outward so it locks into the groove better. Reinstall the snap ring into the diff, making sure not to pinch the ring too tight. You can make sure the snap ring is seated into the groove by pushing into the hub with the back of an X-acto knife. You can then check to make sure the snap ring spins freely inside the groove with the blade of the X-acto. Finally remove any excess black grease from the diff hub by pushing a wrench through the middle. You will now want to apply a bit of diff grease to the diff hubs to help hold the rings on. Coat the diff rings with diff grease before placing the pulley onto it. Fill each of the diff ball holes with diff grease and then insert the diff balls. Next place the other diff hub onto the pulley. Apply a dab of loctite to the diff bolt before inserting into the diff hub. Tighten the diff bolt until the slop is removed and the diff is held together, do not tighten any further yet. Check the smoothness of the diff before tightening any further. The diff will be super loose and smooth feeling with no hang ups. If everything checks out, then tighten the diff 1/4 turn and no more. Again, check the diff for smooth feeling and no hang ups. If everything checks out then check the tightness with a wrench inserted into each diff outdrive. If the pulley turns easily then tighten the diff another 1/4 turn. Repeat until pulley is pretty much locked. It usually does not take more than 2 or 3 of the 1/4 turns to lock the diff down. TIPS TO REMEMBER If your diff develops a high spot then you need to replace the snap ring. When replacing the snap ring we recommend the new HD Snap Ring (SRC79165) offered by Specialized RC. If your diff will not tighten down and acts up no matter how many rebuilds, then you need to check your Snap Ring and/or the sequence of the thrust washers. Be sure to have the smaller OD washer in first. Do not over tighten the diff bolt. You will crush the coned washers and create other problems with your diffs. MAIN MENU