So much for the knowledgeable parts guy, looked like synthetic was in there when I drained mine. And that's what Amsoil has for it. So since you are not an Amsoil fan, I see chain stores are now carrying Royal Purple, that or Mobile one is real good. Just not perfect like Amsoil. Ha ha
I put Red Line Shockproof gear oil in my diffs. The Shockproof stuff is supposed to help protect against damage when the gears get slammed together. There are actually micro-beads in the oil to cushion them.
Why don't they spec synthetic for the front diff then? It seems that there is synthetic in all the other lubricants.
I also found that Castrol makes Import Multi-Vehicle ATF that meets Nissan Matic D and Matic J that can be used in both the transfer case and the automatic transmission. It costs 3.99 a quart at AutoZone.
I am now at 60,000 miles so time to change all the drive fluids (except the trans). I may do a drain and fill on the trans.