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Transaxle Fluid. Do I Change It Or Leave It Alone?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Lexington-76, Sep 13, 2024 at 11:46 PM.

  1. Lexington-76

    Lexington-76 New Member

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    Hi All

    I’m trying to figure out if I should change my transaxle fluid or leave it alone. The manual say only inspect every 30,000 mile but doesn’t say when you should change it.

    I watch The Car Car Nut on YouTube and he advise (at least for the Lexus), that if you haven’t changed your transmission fluid before the 100,000 mile mark don’t change it and leave it alone. Well I’m at 100,000 and I’m trying to decide if I should change it or leave it alone. My assumption is that since the car is a Hybird that the transmission doesn’t work as hard compared to a normal gas engine car. Any advice here would be appreciated.

    Thanks
     
    #1 Lexington-76, Sep 13, 2024 at 11:46 PM
  2. BiomedO1

    BiomedO1 Senior Member

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    Welcome Lex;
    The car nut is speaking about a normal transmission with valve bodies and wet clutches NOT a hybrid CVT.
    I'm of the opinion that you should change it, just to remove the break-in wear material and other nasties floating around in there. Actually your transmission is working harder than a normal transmission, because of the two electric motors within. Your transmission may work independent of your ICE and move the car up to 10 mph before requiring the ICE to kick in.
    While the transmission on these cars don't fail too often, I just like to give it a leg up and consider it cheap insurance.

    Hope this helps....
     
    #2 BiomedO1, Sep 14, 2024 at 6:26 PM
  3. ColoradoBoo

    ColoradoBoo Senior Member

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    I agree, go ahead with the change....it's as easy as doing an oil change BUT be ready for very tight hex bolts if they haven't been open in 12 years. (My Gen 4's have 10mm hex bolts.)
    I found it easier to snake a tube down the back of the engine bay to refill mine instead of pumping up the fluid...I hate those hand pumps.
     
    #3 ColoradoBoo, Sep 14, 2024 at 7:12 PM
    BiomedO1 likes this.
  4. bisco

    bisco cookie crumbler

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    if you are keeping the car long term, change it. if not, i wouldn't bother, these transaxles are almost bulletproof
     
    #4 bisco, Sep 14, 2024 at 8:03 PM
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    The type of work matters a lot.

    The Prius transaxle does not contain any clutches, bands, belts, drums or other friction systems. Therefore no particles are ever shed into the fluid.

    This is fundamentally different from most automatic transmissions, and it's the reason why these cars can go a zillionty miles on the factory ATF.

    If you do change it, insist on the real-deal Toyota WS ATF. I'm sure many other ATFs would provide the right lubrication, but personally I would not take the risk that they might eat the insulation off the windings of the motor-generators in there.
     
    #5 Leadfoot J. McCoalroller, Sep 14, 2024 at 9:01 PM
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