Felt some vibe in the right rear again this weekend so decided to pull that axle and have a look. Plenty of play in there so I'll replace the bearings and seals for sure, and clean out all the old grease and muck.
There appeared to actually be some moisture mixing with the grease though, enough to have a little bit of "dirty water drip" come out when I removed the axle assembly. It was 42-year-old nastiness in there for sure. The car has been garage-kept for almost 10 years, should I be concerned about the oily-grease muck?
You may recall I replaced the busted drivers side bearing a few years ago, but no muck on that side at the time.

Take a good look at the inside bearing race and make sure it hasn't spun on the axle. It's supposed to be a press on fit with no play. If it moves on the axle it means the axle is gone. Seems like I used to replace one side or the other every year when I ran reversed cragars. If the lube bugs you pull the inspection plate and refill with fresh.

The other thin I have done is run a cow magnet down the housing after pulling the axle. It does a good job removing any metallic debris from the housing.

Thanks guys. I have the Carquest guys doing the axle measurements, hopefully it'll pass inspection and be able to be used again with new bearing.

If you do need another Summit sells them or Monaz posts a listing for axles on the FS section every once in awhile. Think I'd be tempted to get a pair and then keep the old one for a spare.

I think I bought an axle from Moser a few years ago when the same thing that you describe happened to me (minus the nasty gunk). So far so good.

What's with right rear axle bearings? I had to replace mine (did both sides while I was at it) last fall.

Granted. I have no way of knowing how old they were, but I started to develop a grinding noise making right hand turns. Drove me crazy for a couple weeks.

I had a bearing cut over half way through my left axle on mine once. Not a good thought of what would happen if I hadn't caught it in time.

if not a posi, I think thats the driving wheel..maybe gets more pressure?

I also think you hit more crap with the right axle, curbs, potholes, stuff laying on the side of the road, etc.

Good to go now, test drive on I-24 at 90 MPH and she is smooth as silk. I would bet that the old bearing was 44 years old.