Originally Posted By: Boss302fan
Many ATF's and PS fluids have close to the same viscosity. Either one will work in 99% of all power steering systems....
There seem to be several different PS system available today (positive displacement pump, variable displacement, electro-hydraulic) and I am not sure one fluid will work for 99%. Once it seemed that most OEMs used ATFs such as DEXRON-II,-III or Type F. Today GM, Ford and Chrysler recommend their own type of ATF (ATF+4, DEX VI, MERCON V, LV). Toyota and Nissan recommend genuine PSF. Honda has a unique fluid having a high viscosity, enhanced anti-wear, and excellent low temperature properties. European OEMs primarily specify dedicated synthetic power steering fluids or Central Hydraulic Fluids (CHF). Many PSFs in the NA market are low performing products. In my opinion European Fluids will work for all except Honda and Dexron/Mercon will work for all for a short period of time and can be an economic choice for many.