I think while I'm doing some PM stuff that I'm gonna do a PS system flush. I know our manuals say to add PSF but would ATF be a better fluid for the system?

 

bump.........

 

ATF has been called for since power steering systems started being put on fords. I know for certain till at least 1991 because it says so in my f150 manual. It called for type F in the 91 F150 4x4.
I think, from several years of working at Ford garages that the switch came from Ford being cheapskates and wanting you to use powersteering fluid with seal conditioners, stopleak crap and other garbage in it to shut screwed up pumps up just long enough to get it out of warranty. FWIW, I have never seen anything but red fluid in anything I ever did a PDI on at Ford so it sure looks like ATF to me. The PS fluid they sell usually looks more like brake fluid.

What I have always done and recommend is cutting off the return line to the pump, and installing a new longer hose on it. Then somewhere in a good place to get to it install a inline magnetic transmission filter. You can get them about anywhere.
Then all you have to do is about every 6 months borrow your wifes turkey baster and suck out the pump and refill it with synthetic mercon atf like mobil 1 or RP or something. Just nothing fancy like the crap for worn out transmissions that has special additives. It's just a simple hydraulic system is all it is and if you change the fluid twice a year and the filter at least once a year then it will stay happy for a long long time. I've never had to replace a power steering component on any of my trucks ever. Well except for a couple pressure hoses. That unnecessary swivel end they put on them is about the dumbest and most leak prone piece of crap I have ever seen in my life. A simple double flared fitting would be so much simpler and would never leak.

 

Awesome. I figured ATF would be better but wanted to verify. And FWIW my owner's manual calls for Power Steering Fluid. I don't disagree with any of your info but for whatever reason that's what she says.

 

I know. Ford changed it in 93 or 94 I think. My 94 powerstroke still calls for atf but the 97 doesn't. I'm sure it's just for warranty crap and no really good reason. The pumps haven't changed in years. I am NOT a fan of snake oils if you haven't noticed yet. PS fluid I consider to be one of these. Ya know I even run mercon in my old tractor. Its a super C farmall. Before with the 30 weight engine oil it called for in the hydraulics the lift was about gutless in the winter. Since using atf in it it's more like the modern tractors trans/hyd fluid and will lift anything any where any temp. That old thing has leather seals throughout the hydraulic system too and has never leaked so it must like it.

 

Ahh, I got ya. I read your first post wrong... To flush the stock system do remove the hose at the reservoir or the PS gearbox? And how many quarts does it take?

 

I wouldn't really flush it. Just drain out what you can when you pull the return hose off. The one that is just clamped on. And refill it. Should be less than a quart. If you flush it you will get air in it and it's gonna make noise for a while or possibly even damage it. Just playing around with the return side you won't get much if any air in the gear box.