Mixing Fluids in Power Assist Steering

[Lin]

My 5a has hydraulic power assist steering.  I have always used automatic transmission fluid in it.  I liked that it was a different color than motor oil to help with leak detection.  The system now uses oil, and I have not been able to find where it is going.  I have been thinking to switching to 30w motor oil and wonder if I can just add the 30w oil to the system as needed, or would draining all the transmission fluid be necessary.

[Geoff]

It mixes fine.

[chessie4905]

Is the pump gear drive or pulley/belt? Leak at gear seal into engine?

[Lin]

It is gear driven.  I guess that would be another reason to switch to oil.

[TomC]

I use 15W-40 in my Sheppard power steering, and when it is cold it howls pretty good for about 5 minutes. If you use straight 30, it might be a real problem in the cold. Good Luck, TomC

[chessie4905]

He mentioned power assist. I don't know if there is a difference in lube requirements.

[buswarrior]

It really doesn't matter what liquid soup you put in there, oil, transmission, mulit, single, mixed...

The fluid is there to be the muscle, not to perform anything fancier.

The pump just wants to push something.

Happy coaching!
Buswarrior

[Dave5Cs]

Power steering fluid = Wix filters SL 10012, Hydraulic oil- ATF Any of these are fine Clifford says the Ross book says. About 5 QTS.
Dexron ll
ATF type E or F        or             
Chevron 10/40
Chevron Torque 5 Fluid
Exxon H 32 Hydraulic
Fleet Line PSF
Ford spec M2
Mack EO-K2 engine oil
Mobil ATF 210
Mobil Super 10/40
Shell Rotella T 30w
Shell Rotella 15/40
Texaco 10/40
Texaco TL1833 power steering fluid
Union 10/40
Union 15/40
Unocal Guardol 15/40 there you go. that is the approved oils for your steering box from the TRW book

[chessie4905]

Tom, if you replace your fluid with the synthetic equiv., it should have stable viscosity, hot or cold.