I replaced my Dana cover gasket 2 times and it's still leaking. I cleaned all surfaces with brake cleaner then used permatex black/gasket/permatex black.

Not sure if this makes a difference but it seems like the GM additive (clear) is leaking first. I'd expect to see brown gear oil (85/140) but both times there's a light film of almost clear fluid dripping from bottom.

Thx