This spring I bought a D30 from a whow wrecked his YJ.

The axle had new ball joints, brakes and  steering and had been
regeared to 4.10
20,000 mi prior to my getting it.

It's been leaking what I think is gear oil from the passenger side
onto the "ear" just outside the axle tube.

I've been checking my gear oil on a regular basis and it has not gone
down.
Thought it could be brake fluid and but thats fine.
I'm wondering when the gearing was done that fluid was put in the
passenger axle tube and its seeping out.

Anyone have any ideas?