Should I replace the transmission fluid on my 2008 Prius with 250k?

Discussion in 'Gen 2 Prius Technical Discussion' started by Banksy, Feb 20, 2020.

  1. Banksy

    Banksy Member

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    I have a Prius I just got with 250k on the clock

    I really am not sure if the fluid inside the transmission has ever been changed. I do understand that the fluid is supposed to be the for the life of the vehicle, but with this many miles I gotta figure that stuff is pretty tired.


    If I swap the fluid with Toyotas brand it recommends will it cause the transmission to slip?
     
  2. SFO

    SFO Senior Member

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    Sure won't, and a great idea. Easy dump and fill job, just be sure to loosen or remove the fill plug before you drain the fluid.
     
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  3. Banksy

    Banksy Member

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    Alright. It's this stuff you add right?
     

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  4. Banksy

    Banksy Member

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    The like would indicate a yes?
     
  5. SFO

    SFO Senior Member

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    Yes, Toyota ATF WS. Best to stick with the factory fill to be safe, be it Toyota WS or Aisin WS.

    Though many here have used nearly everything, from Valvoline MaxLife to Redline/Amsoil, and someone even used engine oil o_O
     
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  6. douglasjre

    douglasjre Active Member

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    It can't slip. Change it
     
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  7. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    If you don't mind: save a little of the drained fluid if you can, and do a side-by-side pic with new.
     
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  8. VFerdman

    VFerdman Senior Member

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    Your car does not have the kind of transmission that slips. It's a completely different creature. It does not shift gears and there really isn't a gearbox. It's an electric motor with a chain going to the final drive. Do replace it and do not worry about slipping (or anything else). I am sure it needs to be changed at 250K miles. Use the stuff you posted a picture of. It's important for it to be WS type because of said electric motor involved.
     
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  9. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    4 quarts or liters should be enough. Correct level is achieved by adding new fluid at the fill hole till it starts coming back out, with the car level. A funnel with about 3' extension tube is a dead simple method to get the new fluid in (with an assistant). Keep tube OD 5/8" or less and it should* fit. There's not a fluid change instruction in the second gen Repair Manual, but there is a check instruction (attached).

    I'd recommend to have a preliminary look, see what the bolt sizes are, what's needed. I'm not sure what's involved with second gen, but 3rd gen for example, a 10 mm hex male "socket" is needed for both, and the torque is 29 ft/lb. A long handled wrench (or breaker bar) will be handy, they tend to be glued on. Also, replace the washers: dealership parts department should be able to figure it out.

    Don't shoot me if it doesn't, I've not done a second gen. Again, a prelim scouting expedition would be good: you can check what sort of sockets are needed, and maybe remove just the fill bolt, check the ID of the hole. A slight amount of fluid might spill out, especially if the car is tilting backwards. But not much.

    Oh, and: I've seen a Toyota document that recommends to only use fluid from freshly opened bottles.
     

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    #9 Mendel Leisk, Feb 21, 2020
    Last edited: Feb 21, 2020
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  10. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    #10 JimboPalmer, Feb 21, 2020
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  11. dig4dirt

    dig4dirt MoonGlow

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    FWIW

    Prius "c" uses same 10mm allen, same engine as Gen2, although maybe diff trans?

    Also, I do remember some thread here saying after a high mileage trans drain and fill,
    they jumped up in mpg. not sure if anyone else remembers.

    btw, just noticed you are near me @Banksy
    Let me know if you need a hand or tools.
    may also have one quart left of WS
     
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  12. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Honestly I wouldn't bother. The point of changing it at all is to do it early enough that the extra particulate contamination has less of a wear effect later in life. So there's some logic to dumping it at 50k and maybe having one fewer problem once the thing has 250-300k on it. But only maybe, since Toyota says its good for life and for the most part hasn't been wrong.

    Well you're already there at 250k. There is obviously some more dirt in your oil now, and the car didn't have a problem. In other words, you've already received 80% of the benefit for free, why pay for new oil now? Keep the cash for the next thing. There will be a next thing.

    I certainly understand the desire to protect and maintain a car, but there is a lot of cost in over-maintaining something. You might say it's even enough to sustain a network of neighborhood car parts stores and retail sales of clever formulas.

    This is one to skip.
     
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  13. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I am going to (respectfully) disagree with Leadfoot J. McCoalroller. lets get those suspended metal particles out of your transaxle before they short out a motor. "Pay me now or pay me later" is $100 vs $5000.

    Just my 2 cents.
     
    #13 JimboPalmer, Feb 22, 2020
    Last edited: Feb 22, 2020
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  14. Banksy

    Banksy Member

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    Thanks brother.
     
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  15. Banksy

    Banksy Member

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    Update

    I've just gotten both the bolts off. I waited to change the fluid until I got the car inspected

    These bolts were not torqued to 29ft lbs

    They were extremely tightened on there.

    I didn't notice any damage to the housing of the transmission.

    Do they come from the factory at 29ft pounds?

    Also I don't have a picture of the fluid, but it looks dark however it had a slight tint of red to it.

    I think this fluid was changed at some point from what I'm seeing here.

    Also I didn't notice any metal flakes. A bit of metal looking sludge was on the plug. Right where the magnet part is. There wasn't much at all on it.
     
  16. dig4dirt

    dig4dirt MoonGlow

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    That sounds pretty good then, if you saw some red tint to it.
    Sounds like it may have been changed at one time.

    But years of the plug in there, with water, salt, hot, cold makes them tough to remove.
     
  17. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    You'll almost never see much in there, there are no clutches or friction bands shedding particles in a Prius transaxle, so the fluid stays vastly cleaner than traditional automatics.
     
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  18. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    They probably were torqued to 29 foot pounds, at the factory. Any bolt will take a lot more fight to break loose, especially as the years mount. Again, a long-handled wrench helps.
     
  19. The Electric Me

    The Electric Me Go Speed Go!

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    Party Pooper.
    That's a brilliantly logical argument for NOT doing it. I've got to applaud it.
    But I'm still going to side with doing it.
    Mostly because the OP seems like they are (have done it) going to do it themselves, so we're not talking a big expense here. The labor is the OP's, and the only cost is the fluid itself.
    So in this case? Even though you are correct in pointing out the potential benefit of changing it vs. an earlier change point scenario, is lost, I still think a change could be better for the transmission. Worst case, it doesn't hurt anything or help anything but the fluid is new.
     
  20. Banksy

    Banksy Member

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    What are the best jacking points on the gen 2 Prius?
     
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