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Rattle (Flutter) noise from Transmission at high RPMs

Discussion in 'Gen 2 Prius Main Forum' started by way2coolwheels, Jan 22, 2020.

  1. way2coolwheels

    way2coolwheels Member

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    Well, I haven't been on this site for about a year. And the good news is that it's because the Prius has been performing great! My commute part of the time is 200+ miles, for several weeks at a time, so I've accrued 15K miles since the engine swap and fuel tank replacement. But, now I have a new problem, a loud noise from the transmission (transaxle)
    At first I thought it was valve train noise, sounds like noisy lifters. However, if that were the case, it would occur all the time. This only happens on acceleration and at high engine RPMs. So I got out my "engine ear" and placed it in various places under the hood. The engine sounds normal, but the noise is quite pronounced when the microphone is aimed directly down at the transaxle.
    So, before I go about the task of replacing the transaxle, I thought I'd ask if anyone else had the same problem.
     
    #1 way2coolwheels, Jan 22, 2020
  2. PriusCamper

    PriusCamper Senior Member

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    Put a big super strong magnet on the drain bolt for your transaxle and then after driving the car for a while drain the fluid and see if you catch any larger size chunks of debris. Then replace fluid and see if the noise changes much... Or at least that's what I'd do first... As in going from least expensive to most expensive repairs. The fact you don't have any warning lights and you're already starting to figure it out raises your chances of success.
     
    #2 PriusCamper, Jan 22, 2020
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  3. magnumrtawd

    magnumrtawd Member

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    Check the shield on the exhaust. It may have come loose and now rattles.
     
    #3 magnumrtawd, Jan 22, 2020
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  4. way2coolwheels

    way2coolwheels Member

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    Thanks for the suggestion, I doubt it's the heat shield, but it's worth a double check.
     
    #4 way2coolwheels, Jan 22, 2020
  5. way2coolwheels

    way2coolwheels Member

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    Well, if there ARE metal pieces, it's gonna need a transmission anyway. I forgot to mention, this one has 260,000 miles on it! Nothing good lasts forever!
     
    #5 way2coolwheels, Jan 22, 2020
  6. PriusCamper

    PriusCamper Senior Member

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    1/4 million miles isn't much for a Prius, if there was 1/2 million miles I'd agree... Likewise, if there was warning lights and error codes and metal pieces, yes, I'd agree. But if there were just noises and some debris in there and you got it out before any further damage was caused you'd save a ton of money and your car would back to normal in a matter of hours.
     
    #6 PriusCamper, Jan 22, 2020
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  7. magnumrtawd

    magnumrtawd Member

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    The reason I mentioned the heat shield is I just found my 2010 had that problem. but, I didn't notice it until parked on a windy day. It sounded like loose sheet metal banging on something! The nuts were severely corroded.
     
    #7 magnumrtawd, Jan 22, 2020
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  8. edthefox5

    edthefox5 Senior Member

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    Dump the fluid and check the dump bolt magnet. Then put the fluid in a big mouth container and put it in the sun and see if you see any metal in it.

    There is a bearing that sometimes fails and also It may be the chain is going bad from lack of fluid maintenance. Seen a few chain failures here but mostly rare. Its mechanical so thats why its not throwing a diagnostic failure code.

    Sometimes the inner cv joint fails and it beats up the seal where it enters the trans differential and the trans fluid leaks out that bad seal.

    Whatever it is you need to check the fluid asap.
     
    #8 edthefox5, Jan 23, 2020
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  9. way2coolwheels

    way2coolwheels Member

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    Well, I changed the transmission fluid when I did the engine swap about 15-20K miles ago. I'll drain it again and see what shows up.
     
    #9 way2coolwheels, Jan 24, 2020
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  10. PriusCamper

    PriusCamper Senior Member

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    I suspect that with doing the fluid that recently the likelihood that it will be clean enough to run through a filter and re-use is high...
     
    #10 PriusCamper, Jan 24, 2020
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