RC Turnbuckle Jr.
This may have been covered already, but how much fluid are you guys putting in these diffs? I've noticed that with pretty much every sealed diff I've ever used (1/10th and 1/8th) that if you fill them more than halfway, the fluid will push out. It's not that it's leaking. More that there's too much fluid and when you assemble it and sandwich everything together, there's not enough room for all the fluid. So it's naturally gonna push out wherever it can (bolts and/or seals) under pressure.