Mine's in the shop for several reasons, and this is one of them. It's normal if you think it's normal for this component to run dry eventually. To me, that's not normal.

 

Normal is relative I suppose, but at the rate THIS differential is leaking, it could potentially run dry, but not between normal differential maintenance schedules. It's obvious how you feel about Jeep's quality control given the problems you've had with yours, but what you see in the OP's pictures is NOT a Jeep issue, it's typical of almost all differentials. If there was fluid dripping, I'd be immediately concerned, but what you see here is typical and normal. Just keep your eye on it, PARTICULARLY if you'll be someplace off road and far away from a jeep dealer.

 

It'd take a lonnnnggggg time for your diff to run dry with the residue that's seeping. Hell, even with a minor drip, it takes a long time. Most jeepers spend alot of time going over there rigs, much more so than other vehicles they've owned. You'll find this is common and even somewhat normal for vehicles in general and alot of people out there never even change their diff oil. Easy fix though, remove the cover, clean and scrape, put on good rtv . The stuff from the factory seems to be crap and they barely put any on.