CV axle noise?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by onthewater, Aug 2, 2021.

  1. onthewater

    onthewater New Member

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    I've got a 2011 Prius with road noise which I was sure was wheel bearings but it's not. I have read similar threads but I can't figure this one out. After replacing the wheel bearings twice I think it could be tires or the CV axle but neither seems likely after these diagnostics. What's your guess or how should I proceed?

    - Michelin Defender XT 90k warranty installed at 55k miles, no noise at that time
    - at 75k miles aroaring sound had gotten too bad to be ignored and I replaced the bearings with aftermarket. It seemed to help but not 100%.
    - now at 95k miles it's back full force so I changed them again with OEM Toyota hubs - again a bit better but still there.
    - low pitch roaring sound seems to come from drivers wheel audible from 22MPH all the way up to highway, but most noticeable at 35MPH
    - sound increases pitch with speed
    - no difference when shifting to neutral, not the transmission
    - Decreased inflation from 42 to 35 no difference
    - swapped front/back, some difference but still there - seems unlikely several tires would go bad
    - no sounds when turning at low speed
    - no difference when changing lanes or curves at speed
    - drivers tire has rotational play in CV axle
    - no clicking when starting/stopping
    - tires 6/32" front, 5/32" back mostly even wear, slightly more (1/32") on the inside edge
    - I haven't done balancing because I don't sense any wobble / shaking.
    - I haven't done alignment because the car drives straight and no difficulty with steering

    So I don't think it's tires because of the swapping. CV axle seems like the only thing left but I've read that CV axle problems usually present at low speed with sounds which I don't have. I've got a chassis ear on order and that will certainly locate which tire is loudest. But I'm unsure how to identify whether it's the tire or CV axle. After two DIY wheel bearing replacements I'm now expert at removing the hub so I'd probably just swap the drivers CV axle except I've read some horror stories here about not being able to get the CV axle out or damaging something else while trying to do so. If you recommend CV axle replacement do you have tips on how to do it DIY?
     
  2. ChapmanF

    ChapmanF Senior Member

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  3. onthewater

    onthewater New Member

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    Yeah, I saw that as well. Looks like a nice app but at $100 it's way overpriced. The Toyota service video basically teaches you to do the same diagnosis for free and from what I could gather, half of the content is about 4WD vehicles. They aren't going to be able to tell you which wheel or whether it's the wheel, bearing, or CV axle. That's why I'd rather put $100 to the Chassis Ear. I just need help figuring out where to attach it to and how to interpret the results
     
  4. onthewater

    onthewater New Member

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    I solved the problem! I knew it sounded like a bearing and it turned out it was, but was the rear driver side. That sound really spreads throughout the whole car so it was impossible to locate it in the back. I broke down and spent $100 on a Steelman Chassis Ear. It was clearly coming from the back wheels but it initially confused me because the clips are not the same volume so what I thought was the loud one actually wasn't. My CV axle does have a 1 click / rotation but it wasn't at all tied to the roaring sound I could hear. I would recommend anyone who wants to replace a wheel bearing first spend the $100 on the Chassis Ear to isolate which wheel it is. It's a lot cheaper than replacing a bearing / CV axle which isn't the problem. Running the wires is easiest right out of the fender and into the closest window. Some zipties and magnetic squeeze clips from the dollar store help. I would also recommend two clips per bearing because of the sound levels problem - you need to distinguish what's just a loud pickup vs an actual loud noise. The wheel bearing noise gets transmitted to the other wheel in the rear through the rear beam.
     
  5. rjparker

    rjparker Senior Member

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    So did you replace the front bearings twice before realizing it was the rear? I am seeing more wheel bearing issues lately on gen3s. Guess they are a better problem to have than head gaskets or brake boosters.
     
  6. ChapmanF

    ChapmanF Senior Member

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    I don't think I noticed that with mine the first time I used it, but I definitely did the next time I took it out. I made a note-to-self to try some day to see if I could adjust that ... like, attach all the clips to my desk fan and see if there are any level trimmers inside the box ... then I'd just have to mark things and remember which clip to use on which channel.

    It's just one of those chores I never seem to get around to doing.

    I ended up with a wireless one: there are still wires from each clip to a little cigarette-pack-sized transmitter. Probably more than $100 officially but I got a used one.

    If I had found a cheaper wired version I probably would have bought it. I don't think the wireless one really saves much hassle; you still have to somehow secure the wires from the clips to the transmitters, and find some way to secure the transmitters themselves so they don't bounce around.
     
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