I have a 87 F-250HD 4x4, 460, 4.10, C6, and i was wondering which ATF to use in tranny and T-case, and what weight oil to use in sterling 10.25 and dana 50 TTB. i have a couple cases of Chevron Dexron III///Mercon, will this work well in my tranny and t-case?

 

Pull the dipstick out of your transmission. It should be marked with the type of ATF required. It is most probably Mercon. The t-case uses the same ATF.

I think that the 10.25 rear takes 85W-90 gear oil. Not 100% sure about the front axle, but it is probably 80W gear oil.

Lou Braun

 

An '87 C6 uses MERCON. I don't know about the transfer case or axle.

 

Your C6 will take DexIII/Mercon
The 1356 will take DexIII/Mercon
The Sterling rear takes 80/90 and if it's limited slip, will require additive
The front axle will also take 80/90, but no additive

Cody

 

thanks cleatus.