My manual specifies Hypoid gear oil API GL-5 Above 0°F (-18°C): SAE 90 Below 0°F (-18°C): SAE 80W or SAE 80W-90
as the proper oil for the front diff, but everything I find is XXW-90. Am I safe to purchase a 80W-90 oil or do i need to look for one without a winter rating as It will not likely be below 0 Degrees where I live.
Any help is greatly appreciated. And do I need to replace any gaskets or washers when performing a service on the diffs + transmission

 

I used 80w-90 on mine with no issues! Just beware the fill bolt is a pain to reach and to fill. Other then that easy job, you do not need nothing other then fluids. Maybe if your fill or drain bolt is leaking crush washers, I didnt replace mine!

 

I only did my rear, but would like to add that I got my oil from the dealer, as well as new plugs, just in case. Also, always the fill plug first.

 

Finally ended up doing this recently and I can confirm that fill bolt was a pita. I got it out with a very low profile long wrench and some PB blaster after some difficulty. Then putting it back on was just as bad.

 

I went to go do this two weeks ago and looked it over and said “f that for now.”

I have to replace that axle anyway so I postponed it; I’ll do it soon now that I have the axle. I decided I would pull the axle first, heat it w/a torch and let it cool to un-seize it, then go at it so it would come out easily. . Then I’m going use synthetic gear oil and Lubegard gear oil supplement, so I can forget about it for 100k miles….