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100% drive unit failure rate??

Discussion in 'Model S: Driving Dynamics' started by yobigd20, Oct 21, 2015.

  1. SomeJoe7777

    SomeJoe7777 Marginally-Known Member

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    DU replacements and associated reliability concerns need to be tracked separately for the large DU (all rear-wheel drive vehicles + rear unit in PxxD vehicles) and the small DU (all xxD non-performance vehicles + front unit in PxxD vehicles).

    The vast majority of the replacements have been the large DU. Small DUs are too new for meaningful sample size, but their reliability will be completely different from the large DUs.
     
  2. Majerus

    Majerus Member

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    Looks like K..

    teslarepair_zpsbxezpq1n.jpg
     
  3. Max*

    Max* Charging

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    Then we'll have to agree to disagree. If the noise is "normal" Tesla would not spend their money to fix it. If the noise is not normal, it's a failure. It's not a catastrophic failure, but it's a failure nonetheless. If you prefer, you and apacheguy can call it a "defect".
     
  4. efusco

    efusco Moderator - Model S & X forums

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    Correct
     
  5. taurusking

    taurusking Member

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    I don't think driving style has to do with it...Would Tesla not expect this when they built the car?
     
  6. efusco

    efusco Moderator - Model S & X forums

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    It shouldn't matter how you drive (as long it's not in some intentionally abusive manner like towing heavy trailers or doing hill climbs or something), but I wonder the same thing. I made it 32k miles on one and have gone about 28k miles on my second and am a pretty conservative driver (Lifetime Wh/mi = 305), and Jerry33 is still on his original at over 50k miles and is a serious hypermiler (lifetime Wh/mi ~280). Would be interesting to see a spreadsheet showing lifetime Wh/mi as a surrogate for driving style vs time to first (or beyond) DU replacements.
     
  7. apacheguy

    apacheguy S Sig #255

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    Interesting. I have the same DU in my non-AP car now. There goes the theory that AP cars have V2 unit.


    Me: "The Tesla motor failed in my Model S"

    Friend: "Oh, so what did you do?"

    Me: "Oh, I kept driving it for another 10,000 miles before I could be scheduled for replacement"

    Friend: "Wait, I thought you said it failed :confused:"
     
    • Funny x 1
  8. RAM_Eh

    RAM_Eh Member

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    I don't think everyone is talking about the same thing.

    1. Drive unit failure. The unit stops working altogether and is unable to move the car. This is my definition of a failure.

    2. Drive unit noise. We all need to look at all vehicles that have a motor. If a ICE motor makes noise the mechanic takes apart the motor and replaces the bad parts and you get the same motor back. For an electric motor since there are so few moving parts it is much easier to replace the motor than to look for the a bad bearing. This is the economics of this type of setup...unbolt the old motor and replace.

    I have my drive unit replaced due to noise but I don't think it was a big deal. I come from an electrical background so and electric motor change is no big deal, on the other hand and new engine...very big deal.

    My 2 cents.
     
  9. Dennis87

    Dennis87 Member

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    If a ICE get rod knock the engine has failed. You can still drive many miles with a knocking engine, but the engine have still failed since a bearing is broken and need to be fixed in the end.

    I think the same apply for Tesla Drive Units.

    - - - Updated - - -

    Strange, the part catalog says that model S with autopilot hw must use revision -M or later.
     

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  10. Majerus

    Majerus Member

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    Where did you get that info?
     
  11. mspohr

    mspohr Well-Known Member

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    I'd be more concerned about the "20KW cursing" ;)
     
  12. Majerus

    Majerus Member

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    Maybe the replaced it with an older one without realizing it needed to be a M or later?

    - - - Updated - - -

    I was ;)
     
  13. Zythryn

    Zythryn M3 Silver, M3 Midnight Silver

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    This is the point of disagreement.
    The sound IS normal, however, Tesla doesn't want that sound their.
    They take drive units and examine them closely so they can improve their product.

    Just as creeks are normal in older cars, they still aren't desirable.
    I had an entire battery pack replaced. Nothing was wrong with the batteries, there was an issue with a sensor in the battery pack.
    Engineering wanted the entire pack back so they could go over it with a fine toothed comb. They also didn't want to inconvenience a customer with a multiple day fix. So, they simply replaced the entire pack.

    I've seen three DU replacements between two cars. They all were the milling noise and all started between 12&15k miles. I haven't had an issue in the last 26k miles (we upgraded the other car).

    From my experience, Tesla is getting a handle on this, but are still having some issues.
    I don't know if it is environmental, behavioral, or just the luck of the draw.
     
  14. Rockster

    Rockster Active Member

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    March 2015 build, drive unit started milling sound at 10,000 miles. Replaced at 12,000 or so miles. My previous S was a 2013 with no drive unit problem at 40,000 miles.
     
  15. yobigd20

    yobigd20 Well-Known Member

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    AFAIC, noise == failure. just as someone pointed out above, it is a lesser degree of failure. does or premediate a complete failure where you're totally stuck? i'm not sure, i dont think anyone knows. it is a bearing that gets worn...so plausible. Tesla just proactively replaces them while the noise is occuring but before the actual 'total failure' point. same difference to me. noise is still a type of failure.
     
  16. Johann Koeber

    Johann Koeber Active Member

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    I doubt it.

    Cars here in Germany are probably used more aggressively than in other parts of the world (I know mine is). People drive faster and less laid back on the German Autobahn. That is one of the reasons I like driving in the US, it's very relaxing.

    The DU problems need to be engineered. Elon suggested it is just a relatively cheap part that fails. After Tesla took care of redesigning that part, all should go well.
     
  17. yobigd20

    yobigd20 Well-Known Member

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    completely disagree. the sound is NOT normal. Tesla needs to redesign to stop the bearing from getting worn and causing the noise. (or design something that eliminates the bearing altogether).
     
  18. brantse

    brantse Member

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    The more I read about this issue, the more concerned it makes me. It is amazing to me that they wouldn't have a better solution than what is currently being done. All gears and related transmission equipment should be designed for a somewhat determinate life expectancy (and I hope it's orders of magnitude higher than 20,000 miles). I've read somewhere that it was hypothesized that the failures may be a result of the ball bearings used not having the ability to accommodate transmitted axial loads. If this can't be accommodated with a more appropriate bearing, the fix should be to use a hearingbone gear. I can imagine with the repair costs continuing to ramp, that Tesla is looking real hard at this to determine when a major design change needs to be implemented.
     
  19. FredTMC

    FredTMC Model S VIN #4925

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    clearly the milling noise isn't normal and that's why tesla replaces the DU. I'm sure if tesla is asked on earnings call, they'll give an update on it.

    Since they've done many revisions of the DU I gotta believe that the reliability overall per revision is generally improving.

    Lastly, I'm confident tesla will ultimately get the DU to be ultra reliable. I believe Elon is telling the truth when he said they are moving towards a DU that lasts 1 million miles.
     
  20. AnOutsider

    AnOutsider S532 # XS27

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    If by "normal" you mean something wore or broke down and thus caused the noise? Then I guess it would be normal to hear the noise in that circumstance...

    Whatever you choose to call it, it's not what's desired by Tesla or the owner. If it were "normal" or "desired" it would be there from the beginning and not develop over time.
     

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