[PunchT37]

Originally Posted by Cliff R

That statement is very true, a pure hydraulic system has no need for fluids with friction modifiers. It needs to be the correct viscosity, and function as a hydraulic oil.

+2

WAY back in the day I used Dextron III in all the power steering pumps on my GM vehicles. At some point in the late 1970's or early 1980's (bad cases of CRS going on here) I read or heard someplace NOT to run ATF in power steering systems as it contains friction modifiers.

Up to that time never had a single issue and had been dumping Dextron III into anything I'd owned with power steering with zero issues anyplace. Even so I switched over to using plain old clear hydraulic oil in power steering systems and continue that practice to this day..........

True. A clear hydraulic oil with anti foaming properties is what`s needed.

[mgarblik]

I would agree with most of the posts in this thread. Specifically, Sirrotica and Cliff. A couple of little additions. First, Saginaw steering gears are very tolerant of almost any non-synthetic PS fluid or Dexron ATF. Never had a failure or issue with either. This excludes Dexron VI, do not use that. If the car has hydroboost, Dexron III is called out specifically and not regular PS fluid. So I use Dexron only in those systems. If the car has a Saginaw power rack and pinion steering system, GM recommends PS fluid only and NOT Dexron ATF. This was because of a compatibility issue with Dexron and the Teflon seals in the rack. That combination caused the seals to wear and cut into the housing and cause, "morning sickness" in the rack. (Lack of power assist when cold). As Sirrotica mentioned Honda vehicles are their own weird animal. Using ANYTHING other than genuine Honda fluids in the steering, transmissions, transfer cases, rear ends is a GUARANTEED component failure. It is absolutely nuts how sensitive those little cars are to exact fluids. GM stuff stays pretty happy if the parts are just kept wet with something!

[Schurkey]

Originally Posted by mgarblik

If the car has hydroboost, Dexron III is called out specifically and not regular PS fluid. So I use Dexron only in those systems.

Apparently depends on the model year, and perhaps the vehicle type.

My '97 K2500 with JD7 brakes and hydroboost requires 1050017 GM Power Steering Fluid (or equivalent) GM Specification 9985010, according to the '97 service manual page 0B-26.

[mgarblik]

Originally Posted by Schurkey

Apparently depends on the model year, and perhaps the vehicle type.

My '97 K2500 with JD7 brakes and hydroboost requires 1050017 GM Power Steering Fluid (or equivalent) GM Specification 9985010, according to the '97 service manual page 0B-26.

Thanks for that info. I will check into what the "equivalent " means. The Dexron call out was on the reservoir lid of most GM and Ford hydroboost PS pumps. It aggravated Ford techs having to put "GM ATF" in Crown Vic's and Lincoln Town Cars with hydroboost.!

[Schurkey]

Originally Posted by mgarblik

Thanks for that info. I will check into what the "equivalent " means.

"Equivalent" would have been any fluid that met the GM Specification 9985010.

Of course, nothing stands still, MAYBE that spec has been updated and is no longer current.

[Formulabruce]

Difference between Dex VI and DEX III is ONLY ignition Temp went up on DEX 6 and slightly more anti foaming ingredients.
This is why DEX 6 is Way way backwards compatible.
Transmission fluid doesn't have many friction modifiers because it has clutches you do Not want to slip.
We used DEX 3 in Pontiacs PS all the time at the dealer, But we sold a OTC clear version of PS fluid for the customers to buy as needed.

[Sirrotica]

I'm not sure where you got information that ATF/Dexron doesn't have friction modifiers in it, but this link I provided below will dispell that information. Friction modifiers are certainly used in ATF to keep clutches from chattering upon engagement. Without friction modifiers the transmission will shudder upon the engagement of the wet cluthes.

When lock up torque convertors first came out in the early 80s, we had many complaints about shudder when the locked up, so bad in fact you'd think the dashboard was going to drop into the drivers lap. The torque convertor clutches were redesigned shortly thereafter to stop this common problem.

From Machinery Lubrication publication, the third paragraph talks about ATF chatter, and shudder, in automatic transmissions if not for friction modifiers:

https://www.machinerylubrication.com...-modifiers-use

[Formulabruce]

Originally Posted by Sirrotica

I'm not sure where you got information that ATF/Dexron doesn't have friction modifiers in it ]

I said " Many" , Of course it has some, but not like motor oils.

[Dragncar]

So when you guys are talking about a clear hydraulic fluid is it the 46 we use in industrial hydraulic units ?
What is kind of strange to me where I work is all the arbor bearings on the edgers and the hog with a 300 HP engine uses 46 hydraulic fluid in the giant pillow block bearings..
Everywhere else I have worked used grease or 80-90 gear oil.
Not here and the bearing do not go out.

[Skip Fix]

I know Lee has always recommended GM fluid.

[Schurkey]

Originally Posted by Skip Fix

I know Lee has always recommended GM fluid.

GM transmission fluid, or GM PS fluid? GM windshield-washer fluid?

[Skip Fix]

Power Steering.

[Sirrotica]

I had a five gallon can of 46 hydraulic fluid that I filled my wood splitter with when I bought it. I've definitely used some of what was leftover to top off power steering units in my older GM trucks. It leaks out just fine.

[Dragncar]

Industrial screw air compressors use Dextron and it lasts about 100 hours. Not long at all.
So they buy this clear synthetic fluid from Rodgers Machinery that is stupid expensive and it lasts much, much longer.
I have always wondered if its fluid like the Tractor Supply fluid they use on Street Outlaws to change where their converters stall.
Its thicker than GM fluid.

[Formulas]

If we are going with off road hydro oils we now have a whole new squirrel to chase, semi synthetic? conventional? single weight? multi weight?

my tractor specs out AGCO 821XL .. which is 10x30 weight semi synthetic, oh the humanity