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low rumble/hum from front passenger wheel

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by dfcowen, Jun 21, 2012.

  1. dfcowen

    dfcowen New Member

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    My 2004 Prius (90k miles) recently started making a low rumbling noise that seems to emanate from the front passenger wheel area. When I took it to the dealer they replaced that wheel's bearings, but the noise persists. The noise is not present when driving on very smooth patches of road, but the slightest bumps will trigger it, and it is independent of vehicle speed or wheel direction. (It is harder to hear at high speeds due to general road and wind noise, but it is definitely still there, and at about the same sound level.) It does not sound louder or any easier to hear when I stick my head out the passenger window, leading me to believe the source of the noise is internal of the wheel well. I've inspected as best I can the region in and behind the wheel well for loose parts, but everything seems fine.

    From my reading of other posts, this sounds like it could be a problem with the transaxle. Does that seem like a reasonable conclusion? If so, what do you recommend I ask the dealer to do to test that hypothesis and/or fix the problem?
     
    #1 dfcowen, Jun 21, 2012
  2. edthefox5

    edthefox5 Senior Member

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    Welcome to PC!

    And yes that could be the omnious hum from a failed bearing in the trans. A few reports of that. Go to lusciousgarage.com and search there repair forums as they discuss this and other transaxle failures.
    There's quite a few psosts about it here too. Usually caused by not changing the trans fluid for the life of the car but your miles are rather low so maybe it's a cv joint. Front hum is usally the wheel bearing. I lost my front driver at 35K but you have new bearings.

    I hope your not running the Goodyear Integrity tires because they are terrible and make quite a racket after about 25K. If so Try this: Deflate the front tires down to 25 lbs and do a test ride. See what it sounds like. If not I would have the trans fluid changed asap and take a real good look at the fluid and see if there's any metal particles in it. Use a strainer as it drains. That will tell you if the trans is shot. Should have no particles or bits just a small mount of soft metal on the magnetic drain plug. Search back my old posts as I have a good write up on it and pictures of what a normal trans fluid should look like. Good Luck.
     
    #2 edthefox5, Jun 21, 2012
    dfcowen likes this.
  3. nh7o

    nh7o Off grid since 1980

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    These sounds can be hard to localize sometimes. I wonder about that, since the engine is on the passenger side (in the US), and the transaxle is on the driver side, with the passenger side drive shaft running under the engine. Hopefully it's something else!
     
    #3 nh7o, Jun 22, 2012
  4. edthefox5

    edthefox5 Senior Member

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    Yes sounds are hard to localize for sure specially rumbling as this is not a very quiet car to begin with up front.
    But most posts I have seen complaining of trans hum always say sounds like pass side. And since its a bearing failure thats eating into the case it does not throw any CEL's. It can be quickly localized to the trans with an oil change and careful inspection of fluid.
     
    #4 edthefox5, Jun 22, 2012
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