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Bearing, transaxle, or transmission? Intermittent loud groan.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by underdog, Mar 15, 2021.

  1. underdog

    underdog Junior Member

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    Vehicle:
    2007 Prius
    Model:
    II
    This '07 (260K) has a loud groan that starts at 23 mph and I don't know the cause. The driver's side bearing is suspect because there's a slight vibration on the spring when spinning the wheel. There is zero play when racking the tire up and down and sideways. There is no change in the sound when turning left or right (loading the bearing).
    The odd thing; the extremely noticeable groan will suddenly disappear. Do bearing sounds come and go?
    Could the groan be the transaxle/cv (no torn boots/leaks) what does a failing transmission make a sound?
    (No codes, trans fluid changed 50k ago, lots of potholes).

    IMG_3936.JPG
     
    #1 underdog, Mar 15, 2021
    Last edited: Mar 15, 2021
  2. underdog

    underdog Junior Member

    Joined:
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    Location:
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    Vehicle:
    2007 Prius
    Model:
    II
    Can noisy bearings sporadically stop groaning for 50 miles (a few days) and then the groaning noise come back again? Or is that more indicative of a transaxle?
     
    #2 underdog, Mar 28, 2021
  3. mr_guy_mann

    mr_guy_mann Senior Member

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    A bad and noisy bearing CAN be quiet IF the direction of load on that bearing changes enough that the balls don't ride on the worn spot of the bearing race. The thing is, for something like a wheel bearing that shows up as a growl noise when going straight, but might be quiet when turning the car in one direction or the other. That is a momentary change. It usually won't "go away" for several days at a time. Same thing for the trans.

    A side note- if spinning the front wheels with the car raised causes one coil spring to vibrate while another doesn't- that is usually a diagnostic indicator of a bad wheel bearing (it just don't explain how it goes away for a time).

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    #3 mr_guy_mann, Mar 28, 2021
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