Come to think of it I don't recall and inner seal on the Mopar axels that I've been exposed to that includes 8.25, 8.75 and 9.25., thats not to say they are not supposed to be there, i just dont recall seeing them when recently working on my 2001 van and 70 Duster with the 9.25/8.25. Fast forward to fixing the leaky axel on this 74 Duster with the 8.75.
It has been some time now that I have have replaced the seals and tapered bearings on the 8.75s in a few B bodies that I've owned, I just don't recall seeing or replacing an inner seal and wondered what holds the grease in the bearings...the inner seal.
A quick Google search and a visit to Doctor points me to the tapered bearing kit or the Green bearing kit which I thought maybe I'll upgrade to that, when I took it apart it already has the Green bearings, which are sealed and looking at the parts included in the kit after reading Dana's post, none is required. The bearing is sealed and aside from a little skinny O ring at the outer edge and the foam gasket not much seems to hold the errant differential oil from sloshing out under spirited driving as in Rusty's post.
Long story I know...so is the seal on the bearing which is hard to see as under the pressed on retainer, the outer O ring or the foam gasket which didn't seem to be in good shape when I took it apart. It does look pretty gunky in there, so maybe a good cleaning, a little RTV and new foam gasket, which has always seemed useless to me, so maybe just some RTV under the outer retainer might do the trick?
