Toyota issued a TSB saying the WS ATF is not compatible with the Dexron fluid used in earlier transmissions (and Dex II or III is what is used in the FJ power steering system). When I buy power steering fluid I aways make sure the labels says "Dexron", "DexII/DexIII", or to avoid all risk, you can buy the PS fluid from the dealer.

Regarding synthetic vs. non-synthetic there usually is no concern with mixing them.

 

aref62,
x2 on what norm356b sez:

Dex II or III is what is used in the FJ power steering system) ... always make sure the labels says "Dextron", "DexII/DexIII",

D

 

Don't use Toyota WS. Use Dex II or III. Valvoline is fine as long as it's got either of those ratings. As for changing it out, it depends on if you have a helper. Since I didn't, I performed the flush with the engine off.

Suck out all the fluid from the reservoir. Disconnect the large return hose at the bottom of the reservoir and plug in an extension hose to that hose. Install a temporary plug on that return barb you just removed the hose from to retain the new fluid you will refill the reservoir with. Stick the end of the extension hose into a container to catch the old fluid. Jack up the front end so that the tires are off the ground to make turning the wheels easy.

Fill the reservoir with new fluid and unlock the steering wheel with the key, but don't start the engine. Turn the steering wheel to either side, lock to lock. Watch that you maintain the fluid level in the reservoir when doing this procedure. You don't want to make the mistake of pulling air into the pump. You'll force old fluid out of the steering rack into the container and pull new fluid into the pump, even though the engine in not running. Do this until you see new fluid coming out that return extension hose. To make things less messy when finishing, suck out the reservior fluid again so that you can reinstall the return hose. Then refill it to the proper level once your FJ is back on the ground and you're done.

A more thorough way is to do this while the engine is idling, but the steering pump pulls out fluid FAST, hence the need for a second person to keep the reservoir topped off. Bleeding this system is a royal PITA, so don't suck air into the pump no matter what.

 

So, the bottom line is the return line? I always thought the upper one is the return since it's easier to get the fluid from the bottom. Also, if it was the bottom one, it worked in case owners forgot to top it up or replace it. At the end of the day having an old dirty fluid is better than having nothing in the reservior!

 

When looking for Dexron III transmission fluid, note that there is no 't' in Dexron. Real Dexron II fluid is rare to find now, but you can still get real Dexron III fluids. Don't use some transmission fluid that claims to be compatible with many different known incompatible fluid specifications that including Dex III. It isn't going in a transmission, it is for power steering use. Power steering systems are prone to leak in the future, so don't aggravate the seals with an incorrect fluid.

Toyota's own Dexron III fluid is called ATF D-III. There are pictures of the Toyota bottle and the Mobil equivalent at this post. Don't use WS or T-IV fluids. For one thing, the viscosity isn't correct.

Australia did receive Toyota vehicles that used dex III so you would expect the Toyota dealers to carry the actual fluid to use when servicing older Toyotas.

As a counterpoint, "The Car Care Nut" on YouTube has said to use Idemitsu Power Steering Fluid and did so on his >600000 mile Lexus when he changed the rack and pinion which is interesting because he is pretty religious about using real Toyota parts and fluids.

 

Note that there is no need to perform a system 'flush' by disconnecting hoses, etc. which increases the potential for grit entering the hydraulic system.

Rather than 'flush', simply drain and refill the reservoir 4-5 times with a minimum of 15 minutes of driving between drain/refill cycles to ensure the the fluid is well-circulated through the PS pump and steering rack. The actual interval isn't critical, you can perform one drain/fill once a week if that's convenient for you.

Drain as much fluid as you can from the reservoir using a 'turkey baster' or large plastic syringe (100cc, etc.), then refill with fresh fluid and drive. Repeat this sequence at least 4-5 times and you'll end up with 95% fresh fluid in the system. Repeat the fluid change every 2-3 years and you'll extend the life of your PS pump and the $$$ steering rack.

Because the power steering system doesn't have a filter of any kind, wear debris from the PS pump and the steering rack circulate endlessly in the system, accelerating wear of all the moving parts. Periodically replacing the fluid is the only way to remove the wear debris.

 

Well, to avoid that debris issue I added an external Magnefine filter, similar to the one I use on the transmission.

 

The MAGNEFINE 3/8” filter extends the filtration spectrum to provide dual filtration that is designed to be completely effective in removing damaging ferrous metal particles from automatic transmissions and power steering systems. When the fluid passes within the effective range (5mm) of the powerful magnet, the MAGNEFINE filter quickly attracts all the hard damaging ferrous particles, even down to an incredible sub-micron level stopping the "chain reaction of wear". (University test show removal of harmful ferrous metal particles to 99.9974%) The secondary filtration media, removes remaining non-ferrous materials (i.e. copper, aluminum, dirt, clutch material)

 

Over the years I've seen several variations of Magnefine-type filters ... some were 'straight-through', and had only magnets, and others have both magnets AND pleated paper filter media. The benefit of the 'straight-through' design is that they could never generate a significant pressure drop and affect transmission operation

What function does a magnet have in a filter that also contains a full-flow paper element? Overall filtering efficiency would be identical if the magnets were omitted, unless the ferrous debris was even smaller than the filtering capability of the paper media?

 

Just a few questions / thoughts.



Do the power steering pumps fail or leak that often?

Is the cause dirty fluid or external causes like dirt and moisture? I guess bearings wear out but that could be for a number of reasons.

If it is not leaking and the fluid seems dirty, why not suck out some of the fluid immediately after shutting the engine off. Doing this may get any contaminants before they have time to settle. Then add fluid, start up again to stir up the fluid, remove more fluid then top off and call it done.



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"Do the power steering pumps fail or leak that often?"

The pump tends to last the life of the vehicle, but the expensive power steering rack on the other hand, the control housing assembly develops grooves where the teflon o rings contain the high pressure fluid.

Back in the '90s it was possible to buy a rack rebuild kit from Toyota which came with all of the various o rings and guides, and you could also buy a new control housing (for about $100) and make the rack new. But today the housing is no longer sold, so the only option is to replace the whole rack, once it begins leaking.

The thought is that regular fluid changes ought to delay when the wear gets to that point.

 

"But there isn't a filter for the brake fluid either. " - true, and it should be replaced regularly too. Ideally every 2 years, at least every 4 years, to get the max life out of the calipers and master. What is being removed is water that gets absorbed by the fluid (it is the nature of brake fluid).

The source of wear in the power steering system would be micro wear particles from the pump vanes and pump housing which rub against each other during use.

 

Since posting the above, I did some research on the only time Toyota ever used a filter on the power steering system, back when Lexus had a hydraulic powered cooling fan (twice the fluid capacity and two separate power steering pumps in one housing so twice the amount of wear material over the life of the vehicle, sharing the same fluid). The hydraulic cooling fan was pretty cool because it was throttle able and nearly silent compared to an electric motor, but cost too much (and a modern PWM controlled electric motor could accomplish nearly the same for less).

The filter used on that system was rated for 40 microns.
Note that most 'power steering fluid filters' are really AT fluid filters, designed to capture chunks of clutch plate material, and might not be capable of capturing something that small. I wasn't able to find any aftermarket PS filters that defined what size particle their filter was designed to capture.

The above sort of reinforces that it is wise to regularly replace the PS fluid to preserve your expensive steering rack, and the source for abrasive material is the operation of the PS pump vanes x housing.

 

That was next on the local dealership's list of things they could screw up. So do I need to use a Toyota PS fluid, or will something else work, since I should probably do that instead of letting them touch it again. YIKES...

 

So do I need to use a Toyota PS fluid, or will something else work?

Read the thread, you can use a fluid rated for DexII or DexIII (it will say so on the label), or if in doubt buy the PS from your Toyota dealer, it will be labelled, "Power Steering Fluid".

 

That's the stuff. Just what I used recently. The OP is apparently having trouble finding Toyota fluids, so he wanted alternatives.

 

It's the smaller diameter hose out of the 2 lines and is easier to access to unplug. The hose that goes back to the pump from the reservior is a larger diameter, faces towards the pump and goes directly to the pump.

Don't accidentally introduce air into the system. Bleeding the system of air is a PITA and will ruin your day.

 

Today, I went to buy the fluid but didn't, since the one I wanted to buy (option 1 - Castrol) was Dexron IIIH instead of Dexron III (3). I checked online and it seems that's the "heavy duty"
version which should be fine, but wanted to double check with you guys to make sure. Here are the options:

1- Castrol Transmax which is Dexron IIIH, and is semi-synthetic (I guess it lasts longer since it's semi-synthetic).
2- Penrite (Australian brand), which is Dexron III but mineral.
3- Valvoline DX-3 ATF Mineral, which is Dexron IIIH and mineral as the name suggests.

As I mentioned, I'm going to buy option 1. Is that fine?

Thanks for your suggestions in advance.

Here are their photos:

 

The local dealer used this kit for the flush they did on my FJ. 🤷‍♂️