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

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Rocketboy235, Aug 27, 2017.

  1. Mdv55

    Mdv55 Active Member

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    Why I mentioned mechanically no difference. Still not sure if the coatings are effected by different lube types or not. All speculation as far I can find.
     
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  2. ChapmanF

    ChapmanF Senior Member

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    ... which indicates something key about what is known, what is not known, and what is speculation.

    That the two applications are similar mechanically: known.

    That the two applications are different electrically: known. A Honda M/T doesn't have electrical windings in the oil. That's a clear difference.

    That Toyota worked on the motor's insulating materials between Gen 0 and Gen 1 "to enhance the oil resistance" so they could eliminate the seal (Gen 0 kept the oil away from the windings): known. (Thanks to Fred_H, posting the Toyota engineering paper in #117 of this thread.)

    That different fluids are equally suitable when there is a known application difference outside of the typical product's testing: speculation.
     
  3. koco

    koco Member

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    The drain plug has a magnet to collect metal shavings, and there will normally be some accumulation of them there; these shavings circulate in suspension in the fluid. Whether or not the fluid itself conducts electricity would not really matter since it will eventually have conductive metal shavings in it.
     
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  4. ChapmanF

    ChapmanF Senior Member

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    At the risk of repetition, what matters is not the conductivity of the oil (or of anything in the oil). The wires are already insulated.

    What matters is what the oil does to the insulation, if anything.

    The Toyota engineering paper linked in #117 reports explicitly that they worked on the insulation formula between Gen 0 and Gen 1 "to enhance the oil resistance" (that is, the motor's resistance to the oil ... not the oil's electrical resistance).

    Anybody who wants to ignore that can. But changing the subject to the conductivity of the oil itself (or particles in it) is missing the point.
     
  5. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Just editorial: for 3rd gen they nixed the magnet.
     
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  6. Mdv55

    Mdv55 Active Member

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    That was an interesting document. It doesn't clarify anything about whether or not their work is only valid if Toyota WS is used and any other lubricant will attack the motors.
     
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  7. ChapmanF

    ChapmanF Senior Member

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    Agreed, it doesn't.

    As already stated, it merely establishes that compatibility of the insulation with the oil was a consideration explicitly engineered for (so, that much goes in the 'known' column), and that "other products not specifically evaluated for that application are substitutable" goes in the 'speculative' column.
     
  8. jzchen

    jzchen Senior Member

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    So, since the "tranny" is gentler than a traditional transmission on the fluid, why is it coming out all nasty looking when people are changing it? What is it that is making the fluid go bad and hence need changing? More directly, if that gunk is not the insulation dissolving into the WS, then what is it?

    REVVL V+ 5G ?
     
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  9. ChapmanF

    ChapmanF Senior Member

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    The first couple questions seem ok.

    I probably wouldn't approach the third question from an angle like "if it isn't (one guess I prefer) then what is it?" One could as well start with "if that gunk is not the rubber of the shaft seals dissolving into the WS, then what is it?" Or, "if that gunk is not some component of the WS oxidizing with the heat, then what is it?" Or, "if that gunk is not some combination of metal filings and dissolved metal from gears and bearings, then what is it?"

    That seems more the kind of question that is usually approached by saying "I wonder what that gunk is?" and then looking for ways to find out.
     
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  10. Mdv55

    Mdv55 Active Member

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    The fluid is pumped onto MG2 to help cool it, which in my car can see 200F in summer. I imagine in hotter climates it sees that temp and then some for a longer period of time. Heat causes fluid oxidation and discoloration.
     
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  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I haven't trotted this out for a while:

    upload_2021-10-15_9-10-48.png

    The above's from the North American third gen owner's manual, and I'm pretty sure there's similar (and maybe more grammatically correct) versions, in 2nd gen, 4th gen, c and v.

    AFAIK this is the only instance in the Owner's Manual, where Toyota says emphatically "use this stuff and nothing but".
     
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  12. Mdv55

    Mdv55 Active Member

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    Most manufacturers warn you against using other fluids that don't meet spec for liability reasons. Of course they want you to stay in house as well. That helps drive sales to their dealers.

    From 2016 Camry manual...

    . camry.jpg


    camry.jpg
     
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  13. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Well they missed their chance then, they could have warned against aftermarket motor oil, brake fluid, and coolant. They do have a caution regarding the coolant formulation, but no emphatic insistence.
     
  14. Mdv55

    Mdv55 Active Member

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    They say to use Toyota engine oil or equivalent that satisfies their requirement. It's the same with coolant.

    Perhaps they have never tested/approved an "equivalent" ATF that meets their WS spec.

    I know a few companies claim to meet the spec, but Toyota may have never signed off on those fluids.
     
  15. ChapmanF

    ChapmanF Senior Member

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    For whatever reason and whatever it means, that definitely seems like a possible takeaway.
     
  16. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Pretty incompetent chiselers: say use Toyota ATF WS, and then don't specify a change interval. :ROFLMAO:

    And then: up here I can get the it through dealership parts department for $9.14 CDN per liter. What's that, maybe $6 US per quart, lol. They can't even succeed as price gougers, lol.
     
  17. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    I just checked, and you can get Genuine Toyota ATF – WS from the mother ship for less than $10/qt.

    Why would somebody try to cheese out and potentially wreck the (not-a-)transaxle to save a few bucks?

    If you're going to be that kind of frugal then you might be better off following the OEM spec for ATF fluid change.... :ROFLMAO:
     
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  18. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I think they leave the alternates on the table?

    upload_2021-10-15_11-8-32.png
     
  19. jzchen

    jzchen Senior Member

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    Well Toyota lawyers are smart. If they told customers to use only Toyota motor oil due to US laws they would be required to give it free during the warranty period. The law states that if a manufacturer requires one specific product to keep your warranty, then the manufacturer must give that product for free through the warranty period. Since they did not have a transmission fluid change interval, they just saved themselves lots of money as opposed to saying it needs changing every 30k mi then needing to pay for all those 30k mi changes...

    REVVL V+ 5G ?
     
  20. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Over my pay scale. For something I'll probably never do again* , and about $40 CDN all in, I'm just smart enough to follow orders.

    * done three transaxle fluid changes, last one I'll dub a waste, drained fluid looked very clean
     
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