Originally Posted by
R40Victim
Go to your LHS and hold a Kyosho/Losi/AE gear up to your Mugen diff, see if the holes line up. I've used a Kyosho plastic spur with AE internals inside a Losi diff housing in my Losi 8ight.
It will also be important to make sure the inner face height of the gear matches or the diff gear mesh could be off. Too loose can be shimmed, too tight and there could be problems.