I've got a bit of a problem with my Dana 44 rear axle. It keep puking out all its lubricant from the breather vent on the top of the brake pipe banjo. There's no leak at all anywhere else, and it seems otherwise to be on good shape. It works, and is quiet in operation (as far as I can tell with the cocophony going on elsewhere in the truck).
I'm deducing that if it was a pressure build-up, the vent wouldn't be venting at all - air, lubricant, whatever. So it can't be that, surely? And it's not over-filled because the filler plug is in the bottom half of the diff cover plate and acts as its own protection from overfilling. It was filled with the truck level.
Other than removing it, stripping it down, and turning it into a big job, has anyone got any better ideas? Or advice on things to look at?