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Hum coming from rear of car

Discussion in 'Model S: Driving Dynamics' started by aaronw, Sep 13, 2014.

  1. aaronw

    aaronw Member

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    #1 aaronw, Sep 13, 2014
    Last edited: Sep 21, 2014
    I am hearing a hum coming from the back end of my model S. The pitch does not change however it grows louder at higher speed. It also does not matter what type of road surface I drive over, but some like grooved concrete make it a lot louder. It is almost as if something is resonating. That's the only thing I can think of because the pitch never changes. I hear it at speeds as low as 40, even on a road that has just been repaved. My other guess is it might be a bearing. It is not the inverter sound and it does not change if I am accelerating, maintaining a steady speed or decelerating. I also have the 21" rims with Michelin Super Sports. Anyone else have this issue?

    Update: The problem is now noticeably worse. It feels like something is grinding in the drivetrain and it is louder and starts at a much lower speed now. I contacted Tesla service but they said they can't see me until 10/13. I think I may end up having to be towed in before then given how quickly things are worsening.
     
  2. AmpedRealtor

    AmpedRealtor Active Member

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    If the noise doesn't change with power input, it's likely not related to the drive unit. I'd have the SC check it out.
     
  3. ahimberg

    ahimberg Member

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    I've got a similar sounding thing I'm having checked out next week at the SC. Though for me I only really hear it above 67mph.
    How many miles do you have? I'm at 14k

    also saw another thread the other day of someone reporting what seemed like a really loud version of this that resulted in a replacement motor or something like that
     
  4. DriverOne

    DriverOne Member

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    Could be one of those loose wires Elon talked about in the earnings conf call. They'd been replacing motors but sometimes it turns out to simply be a wire needed a clip to keep it from touching the motor housing (or something). Take it to the SC for a look & listen.
     
  5. Hodginator

    Hodginator Member

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    I have the same noise which started around 11k and has gotten louder over the last 1.5k miles. The noise can be heard right around 40MPH then goes away until about 65MPH. At 65 and up it gets louder. It only makes the noise under power. In regen or coasting there is no noise. It seems like a humm and vibration at the same time.

    I called the SC and scheduled an appointment to have it checked out.
     
  6. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    When our Model S developed this symptom last April, it was an extremely simple fix by our Service Center, à la Mr. Musk's comments. Here is the write-up from the Service Center:

    Hope your problem is just as easily solved - good luck!
     
  7. Chas F

    Chas F Model S 60kWh #P6396

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    My hum issue sounded exactly like yours. They ended up replacing the drive unit. They send a recording of the sound to HQ and if it is above a certain level, they replace the unit. At least this is what the SC told me.
     
  8. teslasguy

    teslasguy MSP P#1117

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    I also had a hum problem but ended up being the Hvac unit. It goes away if I turn off the climate control. They put an insulation blanket around it and replaced a bracket. Helped some but it's still there and worse on really hot/humid days.
     
  9. mknox

    mknox Well-Known Member

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    Not necessarily. I had a hum that was present whenever power or re-gen was being applied, but went away when the power meter was at zero. I could make it come and go like a switch just by modulating the accelerator pedal. It did not change with power (or re-gen) level. They replaced my drive unit.
     
  10. kcveins

    kcveins delivery 2/7

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    I noticed this same thing - taking the car in next week to be checked out. I'm not sure how long it has been present, though, since I have been driving with the windows down all summer (have 31K miles). Noticed this when my wife wanted to drive with the windows up since the temps were a little cooler.
     
  11. ahimberg

    ahimberg Member

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    re-reading again my symptom is different. The hum i'm getting is just based on speed, not power/regen, its more like a vibrating noise where I thought something might be loose that only makes noise at high speed, hard to pinpoint where its coming from.

    I have always had a high pitched hum/noise at high output power, and sometimes at high regen, the regen one seems to go away once i've been driving for awhile, like something hasn't warmed up, like the high ouput noise seems to always happen at full power but only at 60kw when its near the start of a trip.
     
  12. ChriZ

    ChriZ Member

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    I've had a hum / buzz for awhile coming from the rear but only low speeds 0-10mph. I finally scheduled an appointment to install my center console and reported the sound. They recorded the sound and sent to their sound division and said the drive inverter needs to be replaced.
     
  13. aaronw

    aaronw Member

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    The noise started at high speeds but now it is at fairly low speeds as well. Additionally it feels like something is grinding and is definitely getting worse.

    I spoke to a friend of mine who was one of the designers of the drivetrain at Tesla. He said he knows exactly what the problem is (but wouldn't tell me) and said I need a new drivetrain. Apparently it is a know problem that happens with certain driving conditions to some drivetrains, exasperated by high speed driving. He said there's a redesign for the failing part coming out in the next month or so that addresses it. I contacted service a few weeks ago but they can't get me in until 10/13. I'm hoping I won't need to be towed in before 10/13 or that they'll get me in sooner. Sadly it will be before they have the redesigned part.

    - - - Updated - - -

    In my case it happens all the time, no matter where the meter is and is not affected by acceleration or deceleration.

    - - - Updated - - -

    Nope. Mine is a more serious issue. There is definitely something grinding in the drivetrain and it has nothing to do with what Mr. Musk was talking about. This happens on perfectly just-paved road and has gotten significantly worse. I spoke to a friend who was involved in the drivetrain design who said he knew exactly what the problem is and that they recently diagnosed the root cause and redesigned the part that is failing in some drivetrains. Sadly the new part won't be implemented for another month or so. I don't think my drivetrain will last that long given how much worse the problem is now.
     
  14. aaronw

    aaronw Member

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    I brought the car in and they think it may be the alignment. Apparently they replaced some bolts in the suspension to adjust the camber and the new bolts tend to slip. My tires were scrubbing and there's a lot of wear on them (after only 5K miles!).
     

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