Growling sound while driving

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by BAT PRIUS, May 5, 2026 at 8:17 PM.

  1. BAT PRIUS

    BAT PRIUS New Member

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    My car has started making a growling sound while driving. It gets louder over 60 mph and after 50+ miles at 60+mph, the growling is very noticeable at all speeds, even in town traffic. I jacked the car up and checked all wheel bearings, nice and tight and no growling when I spin them. Put the car in gear and no growling sound when spinning in the air (car was not warmed up when I did this). I suspect the differential. I checked transmission fluid and it is full, but ugly. Will bad fluid cause a growl? Also, I don't have Toyota WS fluid but was told Valvoline Maxlife Multi vehicle fluid is acceptable to use. Should I use it? I have it here right now. Also, the transmission and differential use the SAME fluid, or are they somehow separated inside the trans axle?
     
    #1 BAT PRIUS, May 5, 2026 at 8:17 PM
  2. saneesh8

    saneesh8 Member

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    Change the transmission fluid with Toyota Original .. you can buy from local dealer or shop online..

    The growling with wheel bearing usually changes "tone" with slight change in gas.

    Tires, are they good? Tires, especially winter tires can make noise
     
    #2 saneesh8, May 6, 2026 at 9:18 AM
  3. ChapmanF

    ChapmanF Senior Member

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    There's no separation inside the case; it's all the same fluid.
     
    #3 ChapmanF, May 6, 2026 at 9:20 AM
  4. BiomedO1

    BiomedO1 Senior Member

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    If there's no sound in the air with the car in gear; WHY do you think it's the transmission/transaxle???????????? Isn't it spinning when you had the car in gear in the air???????
    I've had bad wheel bearings that didn't present themselves until you loosened the half-shaft and what about the rear axles. You running that Prius on only two wheels??????
     
    #4 BiomedO1, May 6, 2026 at 9:29 AM
  5. Tombukt2

    Tombukt2 Senior Member

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    Wheel bearings usually present noise loaded with weight . In air almost nothing . Now take stehscope whilst spinning carefully listen to bearing housing rt at axle penetration . You hear the balls moving round scrape scrape etc . Pull it out of ears ya hear nada .
     
    #5 Tombukt2, May 6, 2026 at 9:37 AM
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