I just finished pulling my axle shafts to replace my wheel studs. While I had the differential pulled apart I noticed what appears to be heat spots on the tips of the axle shafts and the tips of the carrier pin. My diff cover was weeping and when I drained it, it didn't seem like I got quite as much out as I should have. However it was not drastically low and the rear end made no noise, and it didn't act up at all. I would like to know if anyone else has found this in their rear differential, and what kind of condition the rest of their rear differential was in.

 

I've seen it before with diffs ran low on fluid. Everything else in them were fine, new axle seals and away they went.