Have searched but had no luck on finding this. I need to know what is the proper gear oil weight for my rear axle? I have a little oil seeping from my outer axle seal on the drivers side. It seems to be the seal behind the flange held on by 8 bolts. I'm taking a trip next weekend and am going to check my fluid level to be sure I am safe, figure I'll have to add a bit but I need to know what weight to buy. Thanks in advance!
Previous owner used only factory recommended fluids at all times so I just need to know what that is.

 

sae gl 5 sae 90 per the good book, but 80-90 was used in the dana 70-80 for a long time too. I run 75-140 synthetic in mine. 1/4 to 1/2 below the fill plug is just fine. If you have the "sure grip" diff and change the fluid be sure to add two mopar friction modifier bottles to the diff.

 

I read in a post that if you use Amsoil no additive is needed. Is this true? Also, would you buy a diff gasket or use the blue stuff?

Sorry for the questions, I need to change mine this week.