TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

High-pitched whine when "idling" above 74 mph

Discussion in 'Model S: Driving Dynamics' started by pgiralt, Apr 30, 2014.

  1. pgiralt

    pgiralt Active Member

    Joined:
    Jun 16, 2013
    Messages:
    1,476
    Location:
    Cary, NC
    I didn't notice this problem until I had my drivetrain replaced because of the 60 mph hum issue, but maybe it was there before. The issue occurs at or above 74 mph, but is most noticeable around 80 mph. It happens when you are right around zero energy usage on the energy meter. I notice it most often when coasting down a hill where the hill itself will maintain my speed of 80 mph while not using or regening any energy. I was told it was normal and have lived it with for a while, but then I got a loaner yesterday while I had a few minor things worked on and lo and behold the loaner has the same problem (and the loaner was a 32XXX VIN which is much newer than my 156XX VIN). Does everyone else have this same issue? It's not a huge deal, but it bugs me when I'm driving with the radio off and I go down a couple of specific hills that I hit every day on my commute.
     
  2. brianman

    brianman Burrito Founder

    Joined:
    Nov 10, 2011
    Messages:
    15,487
    Does the sound change on different street surfaces? Having not heard the sound, my general guess is that if I heard a steady sound at a single speed with the consumption arc at effectively zero I would guess it's the tires.
     
  3. pgiralt

    pgiralt Active Member

    Joined:
    Jun 16, 2013
    Messages:
    1,476
    Location:
    Cary, NC
    It does somewhat sound like tire noise, but it's not. If you give it just a little bit of power or a little Regen, the sound goes completely away which wouldn't happen if it was tire noise. It's definitely coming from the drive unit.
     
  4. mknox

    mknox Well-Known Member

    Joined:
    Aug 7, 2012
    Messages:
    8,570
    Location:
    Toronto, ON
    Gear whine from the reduction gear set maybe? When there's acceleration or deceleration the gear set would be under torque but at "zero" there might be enough slack in the gear system that you get some noise. Just a wild guess on my part...
     
  5. pgiralt

    pgiralt Active Member

    Joined:
    Jun 16, 2013
    Messages:
    1,476
    Location:
    Cary, NC
    mknox - that reminded me to look at what Tesla had said when I had brought up the issue. They stated "Noise caused by slight gear whine during very light load situations" so it sounds like exactly what you said. I was really more curious if others are noticing the same thing.
     
  6. AmpedRealtor

    AmpedRealtor Active Member

    Joined:
    Jun 30, 2013
    Messages:
    4,711
    Location:
    Buckeye, AZ
    While not exactly the same as your issue, my last drive unit droned above 70 MPH, but only when energy usage was at or close to 20 kW. The drive unit was replaced and the issue resolved. I've had two drive unit replacements. None of them exhibited the issue you are describing at 0 kW. My first thought after reading your post was resonance vibration. Tesla has updated the motor mounts, you might want to ask them about whether that might address your issue.
     
  7. SarahsDad

    SarahsDad Member

    Joined:
    Aug 2, 2013
    Messages:
    181
    Location:
    NC
    I've always had a soft whistling/whine while moving (coasting?) at 0 kW. This comes on at any speed above about 25MPH. The tone is different at different speeds; faster gives a higher pitched sound. Even a slight amount of energy either way (+/- 1-2kW) is enough to silence the sound. I'm guessing it's some sort of slack in the fixed gear system - not noticeable enough for me to worry about though.
     

Share This Page