The power steering unit in my truck runs ATF. Any harm if I switched to a power steering fluid? Is there a significant chemical difference between them?
Power Steering Fluids vs ATF
- Thread starter SHAMUS
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yup - the adds can be different but at a base level they are both hydraulic fluids. should not be a problem going that direction.
I tried several difference PSF's an ATF's in '00 MB E430 power steering system, none works as well as Valvoline Maxlife PSF.
Yes, there are differences. Regular PSF is a downgrade. You specified no reason to switch either. ATF has a seal-swelling bias vs PSF. It has more and better additives, namely friction additives. Same with the base oil...better. Think of PSF as "SA" grade oil or Type-F ATF, it's just antiquated slop. If anything, upgrade the ATF in your steering system to synthetic ATF.
Out of curiousity what brands did you try besides the valvoline?
Originally Posted By: Audi Junkie
Yes, there are differences. Regular PSF is a downgrade. You specified no reason to switch either. ATF has a seal-swelling bias vs PSF. It has more and better additives, namely friction additives. Same with the base oil...better. Think of PSF as "SA" grade oil or Type-F ATF, it's just antiquated slop. If anything, upgrade the ATF in your steering system to synthetic ATF.
I don't know enough about seal swelling differences, but otherwise I fully agree with AJ. If ATF is acceptable I'd use it any day rather than regular PSF.
Yes, there are differences. Regular PSF is a downgrade. You specified no reason to switch either. ATF has a seal-swelling bias vs PSF. It has more and better additives, namely friction additives. Same with the base oil...better. Think of PSF as "SA" grade oil or Type-F ATF, it's just antiquated slop. If anything, upgrade the ATF in your steering system to synthetic ATF.
I don't know enough about seal swelling differences, but otherwise I fully agree with AJ. If ATF is acceptable I'd use it any day rather than regular PSF.
I only know about the seal swell from in-depth research on ATF as a replacement for Pentosin.
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Originally Posted By: Audi Junkie
I only know about the seal swell from in-depth research on ATF as a replacement for Pentosin.
Interesting observation:
After using my feed syringe for numerous ATF flushes, the rubber in it has swollen significantly enough that it was hard to use today until there was adequate lube on the walls of the syringe to compensate for it.
I only know about the seal swell from in-depth research on ATF as a replacement for Pentosin.
Interesting observation:
After using my feed syringe for numerous ATF flushes, the rubber in it has swollen significantly enough that it was hard to use today until there was adequate lube on the walls of the syringe to compensate for it.
Kestas
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AJ, I can understand the seal swelling and how it may help a power steering system, but are the ATF friction modifiers needed in a ps system?
I use Valvoline power steering fluid in all my cars. There are no leaks and the systems work fine. I prefer to stay away from the unneeded ATF additives and don't see the benefit of using ATF over ps fluid for my vehicles. It seems that swelling perfectly good seals only increase their wear.
I use Valvoline power steering fluid in all my cars. There are no leaks and the systems work fine. I prefer to stay away from the unneeded ATF additives and don't see the benefit of using ATF over ps fluid for my vehicles. It seems that swelling perfectly good seals only increase their wear.
PS pumps work pretty hard and too often fail. In the process they shed particles into the system. Friction modifiers can only help the situation and should reduce the op temps. I think the degree of benefit depends on the driver and application. fwiw, the Pentonsin PSF is quite thin, when it gets hot the whole system goes into a runaway heating situation.
Originally Posted By: Audi Junkie
PS pumps work pretty hard and too often fail. In the process they shed particles into the system. Friction modifiers can only help the situation and should reduce the op temps. I think the degree of benefit depends on the driver and application. fwiw, the Pentonsin PSF is quite thin, when it gets hot the whole system goes into a runaway heating situation.
I think most cars go to the junk yard without anyone every touching the PS system. I have never had a PS pump go.
PS pumps work pretty hard and too often fail. In the process they shed particles into the system. Friction modifiers can only help the situation and should reduce the op temps. I think the degree of benefit depends on the driver and application. fwiw, the Pentonsin PSF is quite thin, when it gets hot the whole system goes into a runaway heating situation.
I think most cars go to the junk yard without anyone every touching the PS system. I have never had a PS pump go.
Kestas
Staff member
I understand the friction modifiers in ATF are for 'grip', and not for enhanced lubrication. This 'grip' is there for the clutches. The ps system has no need for "grip'.
It's been a number of decades since I've had to deal with ps system problems.
It's been a number of decades since I've had to deal with ps system problems.
I've seen brake fluid do that with some rubbers, but not ATF.
Originally Posted By: AzFireGuy79
Out of curiousity what brands did you try besides the valvoline?
MB recommends Dexron III ATF in '00 E430 Power Steering System and I tried: MB PSF, Preston PSF, Dexron III ATF, M1 ATF. None of them stops the squeal when the steering was turn 10-15 degrees or more. Valvoline Maxlife PSF stops all the noise and the steering effort is back to original, not too light and not too heavy.
Out of curiousity what brands did you try besides the valvoline?
MB recommends Dexron III ATF in '00 E430 Power Steering System and I tried: MB PSF, Preston PSF, Dexron III ATF, M1 ATF. None of them stops the squeal when the steering was turn 10-15 degrees or more. Valvoline Maxlife PSF stops all the noise and the steering effort is back to original, not too light and not too heavy.
I'll bet most all PS systems could use any hydraulic fluid also. I agree, no need for friction modifiers. In fact it would be better if they were not there I assume.
Kestas
Staff member
I'll bet Donald is correct. The manufacturers probably specify whatever fluid is commonly stocked in their dealer network to reduce the need for special inventory.
I have never had a car that calls for ATF in the PS system. Logic would say use PS fluid in PS system, and ATF in auto transmission.
Originally Posted By: Bluestream
I have never had a car that calls for ATF in the PS system. Logic would say use PS fluid in PS system, and ATF in auto transmission.
Logic says use whatever the manufacturer recommends unless you have better source of information than the owners manual.
"Power steering fluid" was rare until the 1970s. Before that ATF was normally used.
I have never had a car that calls for ATF in the PS system. Logic would say use PS fluid in PS system, and ATF in auto transmission.
Logic says use whatever the manufacturer recommends unless you have better source of information than the owners manual.
"Power steering fluid" was rare until the 1970s. Before that ATF was normally used.
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