Steering Power Assist Fluid

[tom.mcinerney]

Both GM and aftermarket offer proprietary "Power Steering Fluid". In a forum post, Ron S. suggests Dexron III.
Question 1: Is there any benefit to using the special powersteering , as opposed to tranny fluids?

Question 2: Are the 'rubber' (elastomer) seals used in the power steering pump , power steering gear, and hydroboost assy subject to swelling/deterioration if exposed to motor oil rather than tranny fluid?

[Hubert]

Maybe someone knows a more complete answer to this but the way I understand it is

Power steering fluid is "hydraulic fluid". Like brake fluid and transmission fluid. Different types have different thermal and foaming properties. Transmission fluid has additive package to keep transmission clutch wear contamination from wearing other parts etc. Transmission fluid is actually pretty harsh stuff it has pretty heavy solvent like properties. They are not necessarily a lubricating oil they are a medium to pump and do work.

Motor oil is specifically for lubrication and has additional additives: detergents etc that help with keeping in solution combustion contaminants (blow by of the piston rings & cylinder wall residue). So they are entirely different oil.

In a pinch a low detergent oil of the right viscosity might could be used for "hydraulic" oil but its probably not advisable to mix different types. I would stay with power steering fluid or find out specifically what it is viscosity and 'package' oil it is.

[Hubert]

duplicate post removed...

[ 01-31-2005, 11:59 AM: Message edited by: ToddMeister ]