Hi there!
Where would you get such a small diff from? Is it true that the Yokomo "Puchi Mru" have a diff? I never saw a photo of this part but would love to. I would need some kind of smallest diff for my new race-chassis ...
4WD is not that easy - I allready tried. But you need "dogbones" (are they really called like this?) and I couldn't make my own (working ones) this small. But I'll keep on trying - there are several TTTT's where the all-wheel-drive (up to 8 wheels!) allready works.
Greeting from Germany!