Question on Transmission Fluid?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by xDuffx, Jun 4, 2019.

  1. xDuffx

    xDuffx New Member

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    Hello, I'm still pretty new to the Prius, this being my first one, but I absolutely love it! My question is what do people recommend when it comes to changing the transmission fluid? I didn't see anything about changing it in the manual unless I just over looked it. Thanks!
     
  2. StarCaller

    StarCaller Active Member

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    original toyota/
     
  3. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Toyota doesn't even detail an oil and filter change in the Owner's Manual, which is sad. Also, they make no mention of transaxle fluid change in the maintenance schedule.

    However: the Repair Manual has the instruction, see attached.

    Also, @NutzAboutBolts has a video on it, pinned at top of 3rd gen maintenance forum (one thread, with multiple videos linked).

    What I do:

    1. Raise the car and get it roughly level. (I raise the front, set it on jackstands, repeat for the back.)
    2. Remove the engine underpanel completely.
    3. Have a catch pan of some sort ready, remove the fill bolt, then the drain bolt. Both bolts are "socket head cap screw" style, require a 10mm hex key style driver. Do not just use an Allen key wrench with cheater bar, get a proper socket with an Allen key tip. Stanley makes a set. (Safest to remove fill bolt first, just in case you have problems.)
    4. Reinstall drain bolt with new washer, torque to 29 ft/lb.
    5. Run a clear plastic tube down from top of engine bay, into the fill hole (about 3' should do, max OD about 5/8", to fit in fill hole.) Push a funnel into the tube.
    6. Pour quarts (or liters) of Toyota ATF WS in. You can pour 3 in without worry, then with the 4th go slow. Best to have an assistant pour in maybe 100 cc at a time, then wait while it flows down. Somewhere around 3.5~4.0 quarts it should start to flow back out, which is the correct level (as long as the car is level). Even if you manage to squeeze all 4 in you should be good. Just feel with your pinkie, the level should be just below the fill hole lip by then.
    7. Reinstall fill bolt with new washer, torque to 29 ft/lb.
    8. Reinstall engine underpanel. (Wash out with soapy water all the plastic fasteners, and replace any broken ones. See attachement for part number info.) (Also apply a little oil to the 10mm (socket size) bolts holding the front of the underpanel. And be careful not to overtighten, especially when oiled, you can snap the heads off.)
    9. Lower the car. Toyota recommends to test drive and then recheck level. I actually did that the first time: waste of time. Just work carefully.
     

    Attached Files:

  4. xDuffx

    xDuffx New Member

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    Sorry I worded that wrong. What I meant was how often is it recommended to change? Mine's under 60k miles so im wondering when I should look into changing it.
     
  5. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Just my 2 cents: first change around 10k (miles), subsequent every 60k. So I would not hesitate, to do a first change.

    Reasoning: I did an early first change, and it around 10k, and it was definitely the darkest. Subsequent changes (2) the drain fluid got cleaner and cleaner.
     
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  6. jerrymildred

    jerrymildred Senior Member

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    Opinions are all over the place on this, ranging from near new to never. I've changed it in my wife's present '07 and in my previous PiP. Both were used cars so I did it early on. The Prime just turned over 31,000 miles. I got it in March at just under 24k. I plan to change it fairly soon. I really don't think there's any kind of a fixed best interval for it because it holds up well, and there's very little friction in the Prius' PSD.
     
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  7. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Professor John Kelly (who has the wonderful Weber Auto YouTube channel) found that the engineers intended to replace the WS ATF every 100,000 miles.
    Like may others here, I recommend one early change, so: 30,000 miles, 100,000 miles and then every 100,000 miles.
     
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  8. ETC(SS)

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

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    +1.

    Make sure that you use Toyota fluid.
    Normally, i would not make this recommendation but in this case it's important to use OEM fluid because your transaxle has electrical (stator) windings that might not react well with other fluids.

    It's almost certain that whatever fluid is used will be just fine, but in this case it's best not to rely on "almost certain."

    It's a very easy maintenance job and the cost should be around $100 more or less.
    If it's much more than that I'd back out and reconsider.

    Good Luck!
     
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  9. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Yeah, getting everything through parts department, you should be able to get out of there for under $40, and the labour's comparable to an oil change. These are my costs (the washer price is robbery...):

    upload_2019-6-5_7-48-15.png
     
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  10. royrose

    royrose Active Member

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    I'm one of the contrarians on this issue. There is zero evidence of "eCVT" failure due to not changing the fluid which is extremely rare in Toyota hybrids. Yes, the fluid gets progressively dark if not changed but that, to me, is not evidence of harm.

    I respect those who who see changing it as cheap and relatively easy insurance and get peace of mind by doing so but I prefer to not do something that I don't believe is needed. Toyota and other car service centers frequently try to sell extra services that are not in the maintenance schedule but they don't push tranny fluid change that they could easily make money on.

    I know I'm in the minority on this among PriusChat regulars, but since you asked, you got my opinion.

    Bottom line, it's your choice.
     
  11. sam spade 2

    sam spade 2 Senior Member

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    I'm right there with you.....but I don't believe "never" is the right answer either.

    I like the 100K range.
    But I will never keep a car that long again ........so my opinion may not count for much. :rolleyes:
     
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  12. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    If I had to choose one change, I'd make it the one year or 10K miles interval.
     
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  13. Raytheeagle

    Raytheeagle Senior Member

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    Our 2019 Prime will get an oil change and atf ws fluid change around 5k miles;).

    Then the next will be a ways off(y).
     
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  14. xDuffx

    xDuffx New Member

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    Yeah I heard some people say never but I just assumed everything goes bad given enough time. Though like you said these fluids do last longer than older cars. Like the oil change for instance how it recommends once a year where im used to owning cars where I change the oil once every three months. I suppose I can make sure to get it at the 60k mark since im fairly close to that anyway.
     
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  15. xDuffx

    xDuffx New Member

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    Yeah guess I should read more about it. I just figured nothing is perfect and that, over time, everything would need to be changed but the hybrid is still new to me so I can surely be wrong lol
     
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  16. sam spade 2

    sam spade 2 Senior Member

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    A few years back, a couple of car makers decided that you NEVER needed to change the transmission fluid.
    They were so serious about it that they did not provide any way to drain out the fluid. I think that one model didn't even have a dipstick to check it.

    They have since backed off of that a bit......partly due to customer outrage.......but there is no good evidence that you will really gain anything except peace of mind by changing your transmission fluid before their recommended interval......unless maybe their recommendation is NEVER, which I don't quite buy into.

    This situation is NOT unique to hybrids.
     
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  17. ThatDudeOrion

    ThatDudeOrion Member

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    I am a fan of frequent fluid changes, and I have changed my Prius transaxle fluid a few times already by 130k miles, but if I'm being honest, I think the factory fill in our eCVT could actually be a lifetime fill based on this specific transaxle design. What I will never understand is the OEM's saying lifetime fill on a traditional automatic trans with the normal clutch packs and steels etc. which create particulate matter and cook fluids. There's a dead MB e320 wagon in my driveway because the trans is in need of a full rebuild(that it will probably never get because is would cost more than the car is worth) at <120k miles and until I see evidence to the contrary, I'm going to lay a big part of the blame on the 'lifetime' fluid mentality.
     
  18. Peter123

    Peter123 Junior Member

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    If I can add a different view here, most automatic transmissions are hydraulically driven. The fluid is used in a torque converter. And, it is used to change gears. Performance is very related to the condition of the fluid. But, CVTs are not hydraulically driven. The fluid is only used for lubrication. It is not under load because there is no torque converter. And, it is not used to change gears. So the concept that you do not have to change it, except perhaps at very high mileage has some basis in fact. However, that being said, I change it periodically too.
     
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  19. bisco

    bisco cookie crumbler

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    except that early change oil analysis has shown a lot of contaminants from what i've read
     
  20. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    It sure looks the dirtiest.
     
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