I did a full system flush and used Valvoline Maxlife Synthetic ATF. It's Dexon II, III and VI compatible (among many others), has excellent flow properties at low temperatures (where I live) and doesn't get cooked as easily in heat. There are some TSBs out for noisy GM power steering systems that specify a flush with Valvoline Maxlife ATF and apparently it's a good fix. Maxlife is a pretty good synthetic ATF and since I figured I'll never replace this fluid again, I figured it's worth a couple extra bucks.

http://content.valvoline.com/pdf/maxlife_atf.pdf

Power steering fluid is NOT suppose to be used where ATF is specified. It will eat seals and rubber lines if the system was not built for it. Many, if not most power steering systems do not use power steering fluid. They use ATF. Toyota specs ATF for our trucks.

Flushing is easy, you disconnect the return line and then start the truck for 5 seconds, shut it off, refill the reservoir, repeat while turning the wheel full left and right until clean stuff comes out the line. Don't let the pump run dry. The original fluid was dirty, although it looked clean in the reservoir. The ATF appears darker in the reservoir, but it's just the red dye.

I added a Wix (re-badged Filtran) power steering filter to the return line. Most power steering failures are due to particle contamination, either through fluid contamination or from wear particles from break in and/or normal wear. Catching them in the filter and magnet can't hurt. The Magnaflow brand of filters is also often used but there were so many horror stories of Chinese fake filters and filters cracking and leaking in cold temps that I went with the Wix. I've used it down to -40 without any problems.

Out of curiosity where did you hear that about the power steering fluid? My old dealership used power steering fluid pretty regularly (mainly because on some PS pumps back in the old days it would quiet their noisiness down) and we had no issues with seals, pumps, or racks failing prematurely due to that.

I've heard it many times from different mechanics and read about it several times on online forums. My Mazda used ATF and if I recall, was not tolerant of PSF. Many Honda's require specific fluid or you can bank on the system leaking.

If the manual and the cap say Dex 3, I used Dex 3. If it says PSF, I use whatever type of PSF is spec'd.

Dexon 3 ATF is an old specification but it's a pretty good lubricant, used for years and millions of miles in transmissions with far worse stress on fluid than a power steering system generates. Dex 3 is widely available and you can get good synthetic options cheap.

Well what I have heard is that unless it's a specific fluid type like Honda, BMW, ect. most generic Power Steering Fluid is actually built/formulated much like Dex II with some additional conditioners/additives that work better for P/S systems in particular.

A lot of people don't really change out their P/S fluid regularly so as you said stuff builds up and takes them out. In Toyotas they seem to ride out the seals into an oblong shape and seep into the inner tie-rod boots more than anything else (from the few people who I know who did rebuild old racks at that point the aluminum housing is worn a bit and even if you put a new seal it'll just leak out again because of how the bore wears).

I'm not saying your wrong, I'm just curious because as I said we used PSF from MOC, Valvoline, and BG at my old dealership and didn't really see any long term issues (even ran it in my 4th gen before I just used straight ATF in it recently).

This is what I used... Says Dexon III on the back of the bottle. Looked like a safe bet to me as its exactly what is called out for in my service manual.

Castrol Automatic transmission fluid 03520C - Read 3 Reviews on Castrol #03520C

Generic PSF isn't really that special of a product. The vehicle specific stuff I'm sure is intentionally formulated for a specific system. But generic stuff is, if I recall, just mineral oil. ATF has detergents, seal conditioners and friction modifiers. I believe it's a superior lubricant - particularly the newer synthetics.

The Valvoline Maxlife ATF that I used has an advertised pour point of -48c. It gets down to -40c (also abot -40f) in my area and regular fluid is as thick as tar. It can be difficult to turn the steering wheel for the first few miles until the fluid warms up. That's really hard on everything in the system - the pump is straining to push PSF that's nearly solid, the seals and hoses are experiencing extreme pressures they weren't designed for etc. I have blown power steering seals out of a rack and blown high pressure lines on other vehicles when on cold mornings, I simply pulled out of the driveway.

Synthetic ATF is not only a good lubricant, it stays much more viscosity stable through a range of temperatures hot and cold, providing less wear.

Sorry to rebump an old thread.

I did the power steering pump about 4 years ago on my 06. Even though it says ATF I used prestone asian synthetic PSF.

It now has 138000 miles, dead quiet, no leaks, perfect steering feel.

In my 08 I changed the pump and used ATF. Its noisy, steering feels a little looser and its louder on start up.

Like Blackworks said power steering fluid is basically ATF with added conditioners and anti foam agents.

I am going to flush out the ATF out of the 08 and use the PSF.

so the toyota engineers were wrong for specifying dex2/3? if PSF was the same as ATF, toyota would have said that either was ok.

the issues you describe in your 08 are most likely due to the change of the pump, not the ATF itself. aftermarket p/s pumps are notorious for not working or being noisy compared to original OEM pumps... on any make of vehicle.

some p/s systems are designed for ATF, some for PSF, some for brand specific fluid... yes other fluids will "work" since they are all hydraulic fluids & wont cause a catastrophic failure, but i prefer to stick with what the engineers designed the system to use.

Are these the same engineers that designed the v8 exhaust manifolds that crack, the ones who designed the wonderful seizing calipers, the ones who designed our uncomfortable seats, who designed an airpump that fails and put it under the intake yet does not warranty them but all the other vehicles that have 4.7s are covered. I could keep going.

I replaced both pumps with OEM. there are certain things I only use OEM.

So you dont use synthetic fluid anywhere? Engineers designed our vehicles to use conventional fluids yet synthetics are superior. most everything in a vehicle can be improved on. As I said before ps fluid and dextron are interchangeable. On most vehicles if you run low on ps fluid, trans fluid is an acceptable replacement.

Ps fluid has additives that will make the system operate better yet trans fluid will last longer so it would help with longer maintenance.

This argument could go on forever its all up to what the owner is comfortable with.

I've always used Dex III on my toyotas, occasionally I'll top off with TIV if thats all I have. Very close fluid to Dex.

DexIII can still be purchased at the dealer, its just called "Automatic Transmission Fluid" but its just good old DexIII. It can also be purchased from any GM dealer, or place that sells ACDelco fluids, in the AC bottle it's just called "Manual Transmission Fluid" all the same stuff.

big difference between a part or system being designed for a specific type of fluid than there is a part failing or a seat being uncomfortable...

brake calipers seize mainly due to climate, winter states have far more seized calipers than southern & western states, my 08 sport has original calipers doing fine at 145k, in iowa!

my seats are very comfortable compared to other vehicles ive owned or ridden in, thats all just personal subjective opinion.

exhaust manifolds can crack mainly due to poor metal content during casting, happens on many vehicles, its not the engineers fault that designed them. & again, that doesn't really pertain to using a different fluid than whats called for. i could keep going too.

yes i use synthetic fluids, 75/90 gear oil is only offered in synthetic, i also use synthetic oil when the factory doesnt specify either type, but oil is oil regardless of the base oil type.

the p/s system calls for a specific fluid, dex2/3, yes you can use a synthetic like maxlife that is still dex 2/3 compatible. but using PSF is not what the p/s system is designed for, otherwise toyota & many other companies would say use either or. & the whole, "PSF has additives to make the system operate better" is a myth with no proof, ive read the same for ATF, got any actual documentation to back up that claim? ive probably read just as much on that subject as anyone & there is no proof either is "better"... it comes down to what the manufacturer says to use, & nobody on here is an engineer for toyota, so why question or try to redesign what they say?

as for OEM parts, todays replacement OEM parts are not the same as wht was installed when the vehicle was made. do a search, there arre plenty of comments of people saying teh OEM calipers are not the same as the original installed ones. in the world of muscle cars, parts like ac delco are NOT what they originally were, same applies to most OEM replacement parts these days.