Originally Posted by
CondeAfonso
What tamiya? lol
On my F103GT I just place the conic washers and tight the nut all the way through. There is no adjustment there what makes it super simple, the washers give the right pressure and it runs smoothly. Just need to sand the plates to make sure the spur doesn't slip. Only problem is the normal diff balls oval fast, so it needs frequent rebuilds. I'm thinking on ceramic to make it maintenance free.
If you are screwing the nut right down you are crushing the cone washers flat and not having any compression on the diff. It will also limit the amount of rear grip. If adjusted correctly the spur won't slip and the diff will last for ages between rebuilds, and the rear end will have much more grip.
With Tamiya F1s you don't need to sand the washers either, just assemble everything with a little ball diff grease. Tighten the diff nut just enough to stop the spur slipping and the diff should be free and smooth. You can then adjust the diff action by tightening the nut a little at a time to stiffen the diff, but the nut shouldn't be less than a quarter turn from fully tight to allow the diff to work properly.