I had the same problem on my old CJ (D44). I think I overfilled it and after tiping (articulating) when hot, the seal failed. Sounds like a fairly easy, but inconvenient and messy fix. I wonder if those fancy external billet aluminum seals would hold better...?

 

I would drain it, put in some inexpensive gear oil and take to be fixed under warranty at the dealership

 

Its got 4.88 Gears and an ARB air locker in it. I dont think they will fix it under warranty. That would be nice of them though.

 

I dont know about the external seals although that would be an easy fix. But i cant see having to put 3 gallons of diff fluid in it to fill up the axle tube to get the depth of fluid correct in the diff. LOL