When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am surprised at the extreme difference in viscosity of the two recomended oils for the zf s6-40 transmission. The GM oil has a viscosity of a 10w30 and the castrol has a viscosity of a 10w60.
I was in a hurry and put Mobil 1 10w30 in mine, but I am not sure if this was a good idea. Normally it seems to work fine, but in a couple instances of a hard high rpm fast first to second shift I have gotten an ugly crunch.
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Originally Posted by rjrjs
I am surprised at the extreme difference in viscosity of the two recomended oils for the zf s6-40 transmission. The GM oil has a viscosity of a 10w30 and the castrol has a viscosity of a 10w60.
Maybe the current (replacement) fluid is 10w-30, but the original fluid was 5w-30.
I wouldn't use standard motor oil in a ZF (even though the Castrol is "motor oil". I know other's have used Mobil products in their ZF but I'm not sure about their motor oils.
Without the correct modifiers, it's possible to "compromise" sychro function. (Slicker fluids slow match-up and vica-versa.)