Transmission Jerking Badly in ECO Mode

Discussion in 'Gen 3 Prius Main Forum' started by dc101, May 10, 2021.

  1. dc101

    dc101 Junior Member

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    Hi Prius experts, Need urgent help with daily driver, 2013 Prius standards 4 door with hatch. This morning when I came to stop at a traffic light, the car suddenly started to shudder when I tried accelerating it.. If could not go above 12mph without causing severe shudder.. Never had any issues ever before.

    I then switched transmission from "D" to "B". and after a little shudder, it started driving fine. I was able to get home. I was able to reproduce the problem. "ECO" with "D" caused really bad shudder and no acceleration. I tried driving in "Power" mode and it drives OK.

    Not sure what is going - any ideas. Thanks
     
  2. SteveSco

    SteveSco Junior Member

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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    How many miles?
    Engine coolant level (in reservoir) stable?
    Hybrid battery charge indicator goes up/down slowly, no sudden drops or jumps, never down to one bar?
     
  4. rjparker

    rjparker Senior Member

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    Is this it? Somewhat chronic on 2010-14 with higher miles.

     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    2015’s immune?

    The transaxle bucking tends to be “just the messenger”; instigator is often coolant getting by the head gasket into cylinder (usually #1), making compression harder, and this reverberates down the piston arm, crankshaft, to the damper between engine and transaxle.

    my money’s on 180k miles, never heard of Exhaust Gas Recirculation. .
     
  6. rjparker

    rjparker Senior Member

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    Less likely because of reduced oil burning. Lots of clean egrs on 2015-17 gen3s.
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Sceptical here.

    I appreciate you know your stuff, but I don’t see it being down to the oil rings. FWIW our 2010 has zero discernible oil consumption at 90k kms, but the cooler was carbonning up nicely when I got to it, about 3 years back.
     
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  8. Mdv55

    Mdv55 Active Member

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    EGR and misfires doesn't jive with the happening in different modes though.

    It shouldn't matter of it is in ECO or PWR, driveability would be the same.

    The fact it's not points to something else going on.
     
  9. dc101

    dc101 Junior Member

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    I did not see any warning lights so didn't check the codes. I will do that anyway to be be on the safe side.
     
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  10. dc101

    dc101 Junior Member

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    The mileage is 271k. No mods, everything standard. Coolant level stays at middle. Just completed a 500 mile trip without any issues. Also, in "B" mode it drives fine.
     
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  11. dc101

    dc101 Junior Member

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    I also want to note that I hear loud clunking and thumping sound when in ECO mode and try to accelerate above 12mph. It seems like something is trying to engage/disengage inside transmission. The sound seems to come from the left side of the vehicle.

    I tested it in turning of ECO mode, initially it drove fine for 6 miles (went up to 60Mph). Once I came to stop at the light, it exhibited the same behavior (without ECO light on). I had to switch to "B" position to drive back home..
     
  12. dc101

    dc101 Junior Member

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    Update: My situation has gotten worse. The behavior now exists for all drive positions (ECO, Power, or normal model). When cold it works on in all positions. As it warms up, starting from stop position, it appears to shift to 2nd gear. In cold condition, it will shift. Once warm, you have to drive it slowly at 25MPH until CVT shifts to 2nd gear and then everything onwards is fine.

    It has now become scary to drive. Is my transmission bad? If yes, how difficult is it to change if I get a used one? thanks
     
  13. Grit

    Grit Senior Member

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    What are the other gears that it shifts through without any issues besides 1st?
     
  14. bettergolf

    bettergolf Active Member

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    Sorry, a cvt has no gears and does not shift. Perhaps the problem you are having makes it feel like a gear shifting? It does sound like the transmission is bad now that all modes are having a problem,.....but that's just reasoning, I'm no expert.
     
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  15. dc101

    dc101 Junior Member

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    Update: I got P301 code. Engine made loud clicking noise. But then it started idling normally. Not sure if a coil is bad and intermittently is acting up? It sounded more like what I have seen in YouTube videos with Head Gasket symptoms. However, I just heard engine's clicking sound first time today. I do know the issue becomes pronounced when car warms up but if you accelerate slowly, you can drive to any speed once it stabilizes.
    I smelled exhaust also and it smells more in alignment with a bad coil (running rich). Not sure what is the quick check for coils without opening so many things.
     
    #15 dc101, May 13, 2021
    Last edited: May 14, 2021
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  16. mikey_t

    mikey_t Active Member

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    When was your last transmission fluid change?
     
  17. dc101

    dc101 Junior Member

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    Previous oil change was about 40k miles ago. I just changed the fluid - but no change in the outcome. The fluid I changed was pink and clean.
     
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  18. Mdv55

    Mdv55 Active Member

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    Sounds like you should be chasing the misfire down and not a problem with the transmission....
     
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  19. rjparker

    rjparker Senior Member

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    Are you losing coolant yet? Coolant loss is a second stage symptom of a head gasket fail as is white smoke from the exhaust. Symptoms sound like head gasket realizing on a Prius it sounds very severe, more like some metal to metal transaxle issue. That is because the head gasket causes misfires which are not recorded at first because they clear up quickly. The clearing quickly behavior separates a hg problem from a coil, spark plug or injector issue which is more permanent.

    Head gasket induced noise IS coming from the transaxle damper, a built in mechanism that takes up some slack when the engine rpms become erratic due to misfires. The electric motors in the transaxle have to remain synchronized with the engine to avoid this. Misfires cause erratic engine rpms. Head gasket problems are common. Transaxle shifting issues are not.
     
    #19 rjparker, May 14, 2021
    Last edited: May 14, 2021
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  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Has the Exhaust Gas Recirculation and intake manifold been cleaned?
     
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