4x4 gear oil-I know but what is it?

[hank19-1]

Just perchased a 93 Explorer with 115,000 miles on it. Just got done changing the ATF fluid+filter. Next I want to change the front and rear gear oil. In the owners manual it says the rear takes GL-5 90w oil. Simple enough. For the front Dana 35 it says it takes 4x4 gear oil. OK,what exactly is 4x4 gear oil? Please just tell me what oil you would put in the FRONT and the REAR. I thank you. John

 

[F14CRAZY]

I've used Mobil 1 75-90 in my differentials. It would be best to use a synthetic 75-140 if available, but not critical.