Just picked up a 2004 Suburban with 210K miles and am getting a little noise from P/S pump. Fluid was low and dirty, quieted down after topping off with GM P/S fluid. Brake system has hydro boost.
My question is this; Is it OK to substitute transmission fluid for P/S fluid? If so, what kind? Would the detergent in transmission fluid create problems?
Thanks in advance for comments and advice... Semper Fi!

 

Lots of PS call for ATF. I changed mine with Redline synthetic PS fluid. No issues to dste.

 

Thanks for the tip, will try it!

 

Well, GM calls for power steering fluid, not ATF. I'm not sure I'd want the added detergents and friction modifiers in my PS system. And the friction modifiers INCREASE friction, they don't decrease it. Do you want increased friction in your PS system?

And, you can't say for certain that the components in the PS system are designed to be compatible with the extra additives in ATF. Specifically, the seals and rubber components. If Honda recommends ATF in their PS systems, they designed the components to be compatible with ATF additives. Can't say the same thing for GM.

Besides, why would you even do it? PS fluid is cheap, and you only need like two quarts, even for the hyrdroboost systems.

 

Yea, I'd go with what the manual says. Not sure there is any cost savings in the wrong fluid.

I used a cheap harbor freight pump to pump fluid out, while adding new to replace, and after exchanging about 3 quarts called it good enough around 100k miles on mine. came out fairly black. No real change in steering, but it gave me something to do.

 

I can't speak to using ATF in the power steering, I will say this, once your hydroboost starts leaking you won't have any problems with dirty PSF. My PSF is just as clean and fresh as it can be. Yes one day I'll take out the Hydroboost's (one in the 05 and one in the 06) and rebuild them. Until then I've got very clean PSF in both.

 

Thanks for the input, will use straight power-steering fluid.

 

Thanks for the input, will use straight P/S fluid...

 

gm swapped out the ps fluid on most of the terrains, enclaves with trans fluid as part of a service procedure iirc for quieter operation. the reservoir would get a new label for the update. point being either one won't hurt it but makes no sense to mix them.

 

Welcome to the forum. You might try calling a dealer parts department and give them that part number and they can look it up and tell you what the fluid is and what size the container is.