Suitable substitutes for the Toyota ATF-WS transmission or transaxle fluid?

I *think* ( and hope ) ChapmanF was trying to say that the ICE is the *primary* means of propulsion in a regular Prius Hybrid. If so...then I buy it because that is essentially the case. A Regular Prius can't go very far/fast on electric alone...so I suppose it could be thought of an ICE vehicle with al 'electric assist'.

That view is extremely outdated though now that we have the PHEV 'Prime' variants, etc... which absolutely can go far/fast on electricity alone....with essentially the same system. They just have bigger and more robust batteries and motors.

 

If you take another look, you'll see I wrote "can still be very sensibly thought of as a one-input (engine) one output (to differential and axles) device". I did not say you're forbidden to think of it some other way if you want, but viewing it as an ordinary transmission with a small ability to 'buffer' power is still a view that can teach you a lot.

In a standard Prius, the statement "there is only one 'prime mover'" uses 'prime mover' in the technical sense. A standard Prius never moves an inch on energy that didn't come from its gasoline engine, either right then or at some earlier time. If it is rolling downhill, gasoline took it up the hill. If it is moving on battery power, that power was put in the battery either by the gasoline engine directly through the transaxle, or by regen, recovering momentum that was produced by gasoline.

(This is the point where one wiseacre in the back of the room may point out that if you bought your Prius from a dealer at the top of a hill, and it was unloaded there from a car carrier, then maybe some of your first downhill run did not come from the Prius's own gasoline engine. Yeah, everybody loves a wise guy.)

If you have a Prime or a PiP, then you do have a second way of putting energy into the car that isn't through the fuel filler, and you could then say it has more than one prime mover. But in the standard Prius, the one is all you've got.

So you've got a gasoline engine, and wheels and axles, and between the two a transmission, and the transmission does have a very modest 'buffer' for some brief net surpluses or deficits of energy, no more than about 1300 watthours, of which the car never even wants to use more than 600. (How small that buffer is becomes very apparent if you try to do any useful traveling in EV mode in a standard Prius.)

Except for that buffer, the Prius transmission is very recognizably John Godfrey Parry Thomas's design from 1908. Adding a small battery-buffer to that is a cool optimization, as it allows choosing a smaller engine suited for the average power needs rather than having to handle the peaks, and gives you a place for some energy recovered in braking. But the basic function of the transmission would all still be there without it.

 

Maybe it's analogous to a house with central heating, and the addition of a hybrid system is like increasing the insulation, reducing drafts and so on.

You're basically recouping inertial momentum (created by the engine), storing it in a battery, using it to drive a motor.

 

@ChapmanF @Mendel Leisk @tvpierce @edthefox5 @Simtronic

Anyway..for the definitive source, I always refer to the absolutely excellent Prius3 3 transaxle overview over at the weber auto channel. WELL worth a watch ( as I'm sure most of us have ).

 

Also, Niels Blaauw did a pretty fabulous Blender 3D animation 4-5 years ago, starting from very simplified (and physically impossible) approximations, and gradually building up piece by piece to a complete demonstration.

 

Yeah we have been recommending these for years on this site.

Have had a few conversations with Prof Weber.

 

Yeah..that's why I always pull out the video link whenever transaxle discussions come up.

 

I know you understand this... so why do you insist on repeatedly bringing up the battery in a discussion about the transmission?
Of course all the energy to move the car ultimately comes from the ICE. But we're talking about the transmission.... and the simple fact is that there are two devices that input torque to the transmission: the ICE and the electric motor. They need to simultaniouly spin at different speeds, and the simple planetary gear set allows that them to do that.
The fact that the electricity for the electric motor comes from energy created by the ICE is as irrelevant to the conversation as the fact that the gasoline for the ICE came from the decomposition of dinosaurs millions of years ago.

 

I'm giving this Idemitsu ATF a try, it's synthetic and it doesn't claim to be anything but WS type fluid, Cheaper than OEM which is conventional and not as vague as the other synthetics that claim to be several types of fluid at once.

 

After 10 years, 246,000+ miles and 7 transmission fluid changes with "Toyota WS", I recently changed the trans fluid with:

Amsoil Signature Series "Fuel-Efficient" Synthetic ATF.

This Amsoil product is a 100% synthetic, fuel-efficient formulation engineered to exceed the requirements of original equipment manufacturers specifying low-viscosity oil. This Amsoil product is listed as a 100% synthetic replacement for "Toyota WS".

I'm sure that over the years, Toyota WS has been improved. I'm not so sure that it is 100% synthetic.

I have zero concerns that I'm no longer using Toyota WS.

 

I use walmart 10 w 40

 

You're using motor oil as replacement for transmission fluid?

 

I’m partial to salad oil, myself.

More seriously, anecdotes of the genre “I filled my car’s transaxle with ______ and it hasn’t failed yet” aren’t especially valuable for someone trying to make a reasoned choice among leaving the fluid alone, replacing it with fresh Toyota ATF WS, or replacing it with some other product. See my earlier comment about small effects, and any good textbook on experimental design.

 

do you guys have any confirms reports on the original toyota atf-wfs being counterfeited on line? because if you do.. Ill just go to the dealer and buy it but the price is way more.

 

How much is dealership asking? Cus up here it’s $9.14 CDN, per liter, at dealership.

 

355 posts over saving $35. on tranny fluid?

 

just as an aside, after agonizing over tranny fluid, o/p's engine blew up 2 months later

 

Oops... Ive mistaken it for a coolant cost. Never the less I bought it in the dealer so I can get it over with. I think it was 11 usd per qt.

 

Yep.. apsitively' you're right. But of course I want original. Not blowing up engine or transmission by manny-moe and jack. I bought it in the dealer. Help my fellow American business. I mean Japanese-Americans....

 

Thank you guys for the follow-up. That saved me a lot of time. Boy it feels just like yesterday when I bought the prius and that was already 50,000 miles ago of flawless driving. I think my next project is I might switch to the next step heavier oil. I have 150,000 miles now and I'm using the stock 5w-30 oil. I just the use the cheap synthetic quaker state. Not bad because I still average 43 to 45 miles per gallon depending on where I drive. It eats up about "1-1/2-cup" (not quarts) of oil ever 4500 to 5000 miles. I already dropped my changed oil and filter service to 4500 instead. what weight of oil should I use next?
By the way.., I gotta report to you guys that I changed my tires too 50,000 miles ago to Bridgestone Ecopia EP422. I'm using 1 size bigger 195-65-15. I still have 3/4 of its life and the ride is always perfect. Sport traction with comfort ride. My next tire will be the same.