Help! Torque converter went bad?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Lemonhead228, Aug 12, 2025 at 11:33 AM.

  1. Lemonhead228

    Lemonhead228 New Member

    Joined:
    Yesterday
    1
    0
    0
    Location:
    Mississippi
    Vehicle:
    2005 Prius
    Model:
    Two
    I have 2005 prius with 175k miles. I was driving 70mph on the interstate and try to accelerate but I can hear the motor rev up but no acceleration.

    After this I changed the trans fluid and inverter fluid but nothing has changed.

    I also read up these cars have e-cvt and will hold up for awhile? No clue. Trying to pinpoint my issue.

    I can still take the car around in the back roads like 40-50mph but not the interstate. Driving around town I feel like the car is more sluggish. I usually average 45mph. Now it dropped to 35mph.

    Any help is greatly appreciated!!

    Thanks!
     
    #1 Lemonhead228, Aug 12, 2025 at 11:33 AM
  2. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    45,238
    16,471
    41
    Location:
    Canada
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Well there's no torque converter cause it's not an automatic transmission. But it does sound like some worn gears inside the Power Split Device (PSD) or the eCVT. Seems odd but I suppose it's possible? Another possibility is a worn MG2 I guess.
     
    #2 Tideland Prius, Aug 12, 2025 at 12:53 PM
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    112,709
    51,299
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    any trouble lights? if not, i would look at the standard gas engine areas
     
    #3 bisco, Aug 12, 2025 at 1:39 PM
  4. Hayslayer

    Hayslayer Member

    Joined:
    Nov 6, 2024
    266
    147
    0
    Location:
    USA
    Vehicle:
    2009 Prius
    Model:
    Touring
    What was your display showing for the HV battery state of charge when the engine was revving on the highway?

    Your symptoms sound similar to what happens when the HV battery is draining itself due to the engine being low on power.
    This can be caused by intake and exhaust restrictions preventing the engine from breathing properly under high demand (like highway speeds).
     
    #4 Hayslayer, Aug 12, 2025 at 5:29 PM
    Brian1954 likes this.
  5. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    12,407
    2,198
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Mine was this way with dying Hv battery replaced and slipping stopped. Common actually
     
    #5 Tombukt2, Aug 12, 2025 at 6:46 PM
  6. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    9,695
    5,978
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Agree. A bad hybrid battery will reduce mpg and power. The reality is battery power is used all the time. When it has diminished capacity you lose the ability to add horsepower at any speed and you lose the ability to store regen energy. Low regen storage means low mpg and low added horsepower.

    Even if the hybrid battery is not supplying horsepower it is needed to run the eCvt transaxle, it is needed to run the ac compressor and it is used to supply 12v power when in Ready.

    All without codes in some cases.
     
    #6 rjparker, Aug 12, 2025 at 7:07 PM
  7. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    12,407
    2,198
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    When my HV battery was bad in the '09 I could step on the gas and it would rev into oblivion and go almost no wer
     
    #7 Tombukt2, Aug 12, 2025 at 7:41 PM
(You must log in or sign up to post here.)