Just 4-5 meters from this I planned to exit the ravine. The front tires did not bite to pull me out, so struggled for an hour, back and forth, with the car flexed up and at one point the rear ARB started to leak. It was still locked and eventually I got out of the ravine. No more leaks on flat ground.
I guess that being flexed, reversing (it pushes the ring gear away from the pinion) up on the side of the ravine and a weak aluminum housing allowed the carrier to move and leak.
Guess who's getting a rear truss and a stronger diff cover? I thought I could get away because I had small tires....