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Transaxle Fluid change???

Discussion in 'Generation 1 Prius Discussion' started by aswresm, Nov 4, 2014.

  1. aswresm

    aswresm Junior Member

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    I have a question if I can use Mobil 3309 ATF to change Transaxle fluid on a 2002 Prius ??
    I know that Mobil 3309 Can be used where Toyota T-IV is used , but would it be suitable to be used in my Prius?
    I am asking because I have a 12 pack case of Mobil 3309 setting in my garage Since I used to use it in a Volvo that I sold..
    Any info would be greatly appreciated!!
     
    #1 aswresm, Nov 4, 2014
  2. bwilson4web

    bwilson4web BMW i3 and Model 3

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    The viscosity range:
    oil 40C cSt 100 cSt
    1 Type T-IV 35.3 7.4
    2 Mobil 3309 35 7.2
    3
    4 Type WS 24.6 5.5
    5 Used Type WS 26.1 5.2
    6
    7 Amsoil 37.3 7.5

    Close enough for Type T-IV substitution. HOWEVER, I tried Amsoil and found it 'ate' yellow metal. There was a spike in copper in subsequent testing at 7,000 miles. The NHW11 transmission still has load bearing, bushings. I don't know if the Volvo did.

    I would recommend doing an initial change saving a one cup sample of the drained oil. Make sure the change includes dropping and wiping the pan. Also, keep a one cup sample of the original Mobil 3309. Wait 5-7,000 miles and do a second change and take another sample. Contact me and we'll have three sample tested:
    • original used oil @??? miles
    • Mobil 3309 @0 miles
    • Mobil 3309 @5-7,000 miles
    What we want to see is if any of the wear materials spikes with the Mobil 3309 additives. If no spike, no problem in long term use. We'll also use partial fractions to recalculate the carry-over.

    Bob Wilson
     
    #2 bwilson4web, Nov 4, 2014
    Last edited: Nov 4, 2014
  3. ChapmanF

    ChapmanF Senior Member

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    Also, any transaxle oil used in a Prius ought to be nondamaging to the electrical insulation of the motor windings. It's possible that other transaxle fluids haven't been tested for that.

    -Chap
     
    #3 ChapmanF, Nov 4, 2014
  4. aswresm

    aswresm Junior Member

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    I know for a fact that Amsoil has a massive content of phosphorus and Calcium which interacts with the winding insulation and cause a Transaxle deterioration ....The thing is I think that Mobil 3309 doesn't have that much phosphorus and other additives as Amsoil..
     
    #4 aswresm, Nov 4, 2014
  5. bwilson4web

    bwilson4web BMW i3 and Model 3

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    That is why we send the first two samples for analysis:
    1. Virgin sample so we know what it is starting with and the 40C/100C viscosity
    2. Used sample to see what was there for the 'carry forward' calculations
    Very important, clean the crud off the pan. I would recommend getting a new cork seal too as the older ones tend to get brittle and crack. It doesn't always happen but often enough.

    GOOD LUCK!
    Bob Wilson
     
    #5 bwilson4web, Nov 4, 2014
    aswresm likes this.
  6. kutcht1

    kutcht1 Member

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    I had read everywhere on the Volvo sites that Mobile 3309 "IS" Toyota IV fluid, same stuff different bottle as Aisin Warner makes the transmissions. Not sure of the Prius CVT. I remember using Castrol multi which lists it is for the CVT transmissions.
    TomK
     
    #6 kutcht1, Nov 5, 2014
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    My inclination would be to recycle the fluid you have and buy the spec'd Toyota fluid for the change. Cut your losses: it's a minor expense, saves you worrying, avoids compatibility issues.

    I'm a fan of "just in time" purchases: buy just as much as you need (say up to one quart/liter surplus).
     
    #7 Mendel Leisk, Nov 5, 2014
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