I drove about an hour on my SD and tore it apart to check it. The grease looked fine considering it's a new diff. When you get a 'new' diff and run it that long the oil is usually pretty greyish. This grease looked slightly used but not by any means bad. I'll run it once more and clean it well and regrease.
I've considered trying Mobil 1 synthetic in this diff. Mobil 1 synthetic is the best grease I've ever used. If you only knew how many greases I've used on my cars that statement would mean a lot. It seams to completely nullify shearing wear. It is a must on outdrive shafts. I'm so picky about it my SD outdrive shafts have mobil 1 and the internals have the losi grease. I could have used the losi grease on all of it. So, I think I'll be trying that grease some time soon. If it doesn't work out then at least I know the lois grease is good.
The only problem I had is that the front bearing popped the rubber seal off and crammed a lot of dirt in it. Sprayed and blew it out then repacked it and it should be fine.
Ben