Sorry if it seems as if this is being beaten to death guys, but what would be the best amsoil to run in my diff's? I have the Dana 80 in the rear, and I assume the 60 up front. I was thinking of going with the 80W-90 in both because it's a tad cheaper/qt. I do not tow regularly, but it tends to get heavy when I do. Alot of hwy crusing and around town stuff as it's (going to be) my daily driver.
Thoughts.............?

TIA!

 

Your signature does not say 2x4 , 4x4 , auto trans or man.
How do you know if you have the 80 , being that you did put 2500 , I've read that manuals have the 80 , and autos have the 70 , but I do not know that is the case ?
I would put the best Amsoil has for the application , I go by my dealers recomend most of the time , but will double check on some things , I use the Severe Gear with the wide temp spec. , cold & hot weather , and there , If I remember it was 80w-120 .

 

I have the HO and NV5600 with 4x4. I know I have the 80 because of the big "80 stamped on the housing. It has disc brakes in the back as well.

 

I have the HO and NV5600 with 4x4. I know I have the 80 because of the big "80 stamped on the housing. It has disc brakes in the back as well.

 

I put the 75w90 in mine when I bought it in 99. The lighter oil gives less rolling resistance(= more mpg) and the severe gear full synthetic has more then enough lubrication and protection. I don't tow on a regular basis But I've haul bricks, gravel and firewood. One run was cab high wet oak from NY to VA in mid summer(9 hrs straight through).
I check it yearly but haven't changed it yet because everything looks good in the oil for 9 yrs now.

 

If you go to the Amsoil site you can input your truck in the "product lookup guide" (right hand side of the screen here. http://www.amsoil.com/index.aspxIt will tell you what is recommended for it. Some with LSD recommend a heavier oil.

 

I Use Severe Duty Amsoil 75-140!