My S8 International had a Funk power shift, they told me i had to use their power shift oil or I'd have problems. I can't remember what it cost but it was spendy. I got to be friends with their trans mechanic he told me not to waste my money. He told me to use Series 3, 10 weight motor oil, so i used 518 Cenex after that. I used it 10 yrs with out a problem.
