crunch-like gear noise when driving on uneven sandy/dirt roads

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by chinarut, Jun 30, 2023.

  1. chinarut

    chinarut Junior Member

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    we have few unpaved roads in this part of town and occasionally when the road gets uneven, I slow down to less than 5 mph and sometimes hit a really sandy part of the road. then I hear a loud "crunch" like noise - I'm no expert but I'm guessing its the differential shifting power to the other front wheel?

    Just wanted to know if this is normal (as it's pretty loud (but brief)) and if anyone else has run into this issue?

    It's happened 3 times in the last 9 months and always the same circumstance with one wheel in the sand or really loose dirt (or mud) trying to get traction.
     
    #1 chinarut, Jun 30, 2023
  2. FuelMiser

    FuelMiser Senior Member

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    You could be activating (causing to activate) the Traction Control, which will briefly reduce power to the drive wheels to stop the slipping, light up a yellow caution on the dash and yes, make some odd noise in the drivetrain. You should also feel some pulsing in the accelerator pedal. I'm not sure about shifting power from one drive wheel to another, but it could be.
     
    #2 FuelMiser, Jul 1, 2023
  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    A differential can and should shift power almost silently.

    From your description, I wonder if you are sinking somewhat in the soft sand and just bottoming out, scraping the belly of the car.

    That makes a wonderfully loud crunch.
     
    #3 Leadfoot J. McCoalroller, Jul 1, 2023
    Doug McC likes this.
  4. bisco

    bisco cookie crumbler

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    Or the suspension needs work
     
    #4 bisco, Jul 1, 2023
  5. chinarut

    chinarut Junior Member

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    hey thanks everyone for the replies!

    I had this happen in the rain once and do remember the light coming on along with some noises. This other sound is more of a "gear slip" kind of noise (almost like it's skipping a tooth - at least this is how it sounds to me)

    Scraping the belly of the car does indeed make a bit of a ruckus! the times this has happened, the sound is distinctly more "scrapey" and plastic-like. I'm also quite certain it's not bottoming out - I've bottomed out a 1 or 2 times with a more a low-pitched, dead "thunk" sound resonating from the car body itself.

    The sound I'm speaking to is more high-pitched "clacky" sounding for a split second.

    I've got a webcam, I'll re-enable audio recording again & post though I certainly don't wish it to happen again :)
     
    #5 chinarut, Jul 2, 2023
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