More like 700hp+ but who's counting
I've rebuilt the diff a few times already, fresh Motul 75W90 300 gear oil in there actually. I do have all the bottom pans on, one which enables fresh air to hit the fins directly.
I suspect my sewer pipe of an exhaust runs very close to that area, could be causing additional heat.
The center bushing is oval, and so is the stock bushing. It is supposed to be installed horizontally, but I don't know the reason. It is aluminum as well.
I have a Quaife in there, no clutch, and backlash was set at .003", within spec.
The melting is more excessive on the diff housing side than on the exhaust pipe side, thus I agree this is probably diff heat. I wonder if more fins would help...