[rcrcman]

I use wd40... split the diff and wipe the side gear off thats exposed... drain some from the diff housing leaving the cross pins and gears in place... spray wd40 in to fill and spin the diff while holding the cross pins in with a finger.. turn upside down to drain and refill after a few minutes. Done this for years in 1/8 buggy without any problems. The 1/10 diffs hold so little of oil it will only take a few minutes to do