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Is It ATF or PSF ?

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  • Is It ATF or PSF ?

    In the v 20 # 2 (latest)Machinist's workshop<page 35.
    Testing Penetrating oils.

    Pic. shows Power Steering Fluid and he says ATF, if it is ATF Which one ? There IS a difference.

    If some one could make some sense out of this for me ,let me know.

    If you haven't seen it It is a good read,Subscribe.

  • #2
    I O ,you are right there is a difference, ATF has a red dye in it. JIM


    • #3
      Here we go again...It was a valid Question.


      • #4
        Yeah, but I think there's Ford ATF and everyone else's. Viscosity difference IIRC and maybe others. I suspect it doesn't matter for these purposes.

        That was an interesting and enlightening comparison. I wanted to know how Farty Arty's Nut Buster compared, but they didn't test it.
        "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill


        • #5
          That is good to know,I have heard that if a tranny is slipping dump ford ATF in it and sell the car.LOL


          • #6

            To IOWOLF and every one else:

            Yes, the article text says automatic transmission fluid and I fully intended to use ATF, but I obviously purchased the wrong bottle. Testing was conducted with power steering fluid. Sorry for the confusion. I don't know how many times I saw that bottle -- adjusting position, setting lighting, framing the shot -- and never actually read the label.

            By the way, for anyone who missed the original question:



            • #7
              A mistake? Some of the best inventions come from mistakes.

              Perhaps ATF wouldn't have worked as well.


              • #8
                I don't know how well ATF would work. I'm tempted to try again, with both, just to see if there is a difference.


                • #9
                  At my shop we have always used ATF for power steering, works fine. We only use the mercon if we feel the vehicle really needs it, otherwise we like to put mobil 1 synthetic atf, especially after 1ook miles


                  • #10
                    I enjoyed the writeup. Thanks lbender-

                    And just think of all the money I'll save on Kroil.

                    Civil engineers build targets, Mechanical engineers build weapons.


                    • #11
                      In my first reply I mentioned the red dye, because I think thats the main difference. As comerrm says atf works great in power steering and has for many years. I believe that power steering fluid just is not dyed red and a pint of PS fluid costs more than a quart of ATF. Just my opinion. JIM


                      • #12
                        Power steering fluid is basically just a light hydraulic fluid, because as far as performance specifications go, a power steering system leads a pretty easy life compared to an automatic transmission.
                        An automatic transmission on the other hand leads a much harsher life.High heat, hydraulic functioning in a complex valve body under extremes of temperature, as well as being able to transmit torque through a wet clutch pack requires a different additive pack to make it function under these demanding conditions.
                        The big difference between Ford atf and the others is the design philosophy inherent in transmissions built by Ford versus most other makes.While GM and Chrysler transmissions in their quest for a smooth shift use a higher band application pressure but a fluid requirement that has a low coefficient of friction.Ford designers on the other hand used a lower band application pressure but a higher coefficient of friction in their fluid specification to achieve the same result.It was always a common practice in the muscle car era of the 60's and 70's to use Ford atf in a Dodge or Chevy in order to firm up the shifts in those transmissions because of the "stickier" fluid.
                        The price difference is basically due to marketing conditions, because although atf is more expensive to manufacture, it is sold in greater quantities than power steering fluid.

                        edited to add...Hey I almost forgot, atf also has to perform the functions of torque conversion and a gear lubricant!
                        Last edited by Willy; 03-28-2007, 01:57 AM.
                        Home, down in the valley behind the Red Angus
                        Bad Decisions Make Good Stories​

                        Location: British Columbia


                        • #13
                          Originally posted by Chipslinger
                          That is good to know,I have heard that if a tranny is slipping dump ford ATF in it and sell the car.LOL
                          Type F ATF has a greater low-speed coefficient of Friction, so it makes a transmission disgned for Dexron shift harder. Used to be a cheap hop-up trick.


                          • #14
                            After putting a shift kit in my 68 GTO a couple of decades ago, I recall that the maker also recommended either type F fluid or their (B&M) "Trick Shift" which I always suspected was type F in an expensive bottle.

                            Now you guys have me are you sacrificing the quality of gear lubricant to get it to shift tighter? Higher co-efficient of friction may actually help the bands last longer...but may cut gear life. Of course, given the normal failure mode for an automatic transmission, this may be a moot point as its usually band failure before anything else.

                            Paul Carpenter
                            Mapleton, IL