So my rear diff seems to be leaking again slightly, most of the back cover is oily right up to mounting bolts so fairly sure I can rule out it being the fill/drain holes.
Couldn't find it again but remember reading in someones build log they had an issue with oil coming out the breather port in the top, anyone else had this issue or know of a solution for it? Not sure what would go wrong with a breather port that would cause it to start ejecting oil out of it unless it was overfilled which isn't all that easy to get wrong.
It's a r180 viscous diff I believe.