I never saw a link on how to do it but the only part that is a pain is removing the diffs from the car. Once you get the diffs out it is only 4 screws you remove, clean out the diffs and replace the fluid with the weight you want. The diffs are inside the housings you see on your car. On the top of the redcat forums page there is a topic about diff fluids and how they work but not how to change them.