I have tried Losi, Associated, Aero Car & Niftech diff lube. The best diff lube of all of them is Niftech Rocket Ring Diff Lube. It works good in my 12th scale & my touring car.. I also polish my diff rings with 1000 gid sand paper. And break in fresh diffs with a my dremel tool. I find a felt polishing tip that fits in outdrive and carefully turn on my variable speed dremel tool to slowest setting. Run tool for a minute, then swap outdrives... Retighten diff, run dremel again. This saves time.. 80-90% of time I never have to retighten diff in car..