Ok got under there with the compressor hose and put it to the end off the diff. Blew through fine as I heard it hissing out of that vent cap up top by the filler neck. I sprayed it all down last. Ought with two bottles of brake cleaner and it still looks almost the same so I’ll have to get more and actually scrub it down it seems so I can see if the pinion seal is actually leaking. I know it’s gotta be due for diff fluid change but I’d like to do it all at once so I’m not having to drain clean fluid again etc so I’ll try and clean it up better today