Being in the trans business for years we have tried just about everything from Type F to hydraulic fluid. Hydraulic fluid is good but it just sucks having to bottle it up and it is hard to come by around here. The farmers eat that stuff up like hot cakes. We have been using type F for the last couple years mixed with 2 quarts of Mobile 1 synthetic. The temps have remained just the same as the hydraulic fluid. I believe when you break it down the hydraulic fluid is actually cheaper but tends to be a little hassle.