Clunking Vibration type sound

Discussion in 'Hyundai Kona Electric' started by blakehaas, Oct 22, 2019.

  1. ericy

    ericy Active Member

    The dealers don't seem to have a lot of autonomy here - they can only follow the instructions they get from Hyundai. When they changed the gearbox, it was probably because this is the guidance that they got from Hyundai.

    And if Hyundai isn't really sure as to what the right fix is (or they are waiting to see if the ones they have replaced already actually solve the problem), then I guess that everyone else goes in the queue. I was hoping that by now they would have a clear understanding of what the real issue was, but I have yet to see any indication of this.
  2. It would be surprising if they don't know by now. Given there isn't an epidemic-level of cases they may be just minimising warranty costs by ignoring it as long as they can, or are still deciding where the blame and liability lies between Mobis (motor) and Hyundai's drivetrain engineering. If there were more catastrophic failures (only one reported in the global FB group so far) such that road safety was compromised there might be regulatory action taken to force their hand.
    It interest me that many complaints anecdotally seem to come from cooler weather regions and the noise appears temperature-dependant. The Kona sells second only to the Model 3 in NZ and I'm certain if there were any such complaints it would be reported in our EV facebook group.
  3. Lots of warranty time left, got to give Hyundai the benefit of the doubt. Replacing the applicable components to this point without a defined resolution is costing them $ on a what so far appears to be a "hit and miss" basis.
    They have been there for me (so far) with any warranty issues so unless something catastrophic occurs, I am willing to wait the course.
  4. wizziwig

    wizziwig Active Member

    Excellent point. It's the same reason why I continue to actively participate in all the threads about this topic - despite my motor and noise being fixed many months ago. I fear what will happen when warranty expires and problem comes back. Without a clear explanation of the cause and solution, it's difficult to have long-term confidence in these cars. Motor swaps are ~$10K repair including labor. As your experience and that of other owners shows, even within warranty, it can be a challenge to get noise issues addressed in a timely manner.

    I wouldn't base my statistics around Facebook (or any social media for that matter). I don't use Facebook and I'm sure many other EV owners don't either - especially for their closed private interest groups. If anything, owners are more likely to post on open public forums because these forums show up in google searches about issues.

    If any of the popular news outlets actually posted a story about this issue, we would probably get even more owners checking their cars and posting about it.
    Last edited: May 21, 2020
  5. Well, I haven't written them off yet. And am really hoping they come up with a definitive solution. This car has a lot going for it, and would be quite happy to own it for a long time. Right size, I like the looks, few little quirks with the FCA and some other driver assist features (that I can live with), great range, nice seats and interior, lots to love. And oh, my wife likes it. She hasn't even noticed the click, clicking, and I haven't told her.
  6. wizziwig

    wizziwig Active Member

    I suspect many owners with the problem don't notice their clicking. I often see people post videos or recordings demonstrating the problem and other owners responding that they don't hear anything in the recording while it's obvious to me. Maybe having owned other much quieter EVs than the Kona/Niro has made me more sensitive to these issues than someone coming from an ICE vehicle. That's why I keep hoping someone runs a story about it to raise awareness.

    Another thing to consider regarding warranties. How long are we expecting KIA/Hyundai to stock spare motors for these cars? The companies have announced new dedicated BEV platforms coming next year. This could be the last model year for these cars before they are discontinued.
  7. ericy

    ericy Active Member

    Car manufacturers are required to supply parts for 10 years. After that, you might be out of luck. If they continue to use the same motor/gearbox then it wouldn't be a problem.

    It remains to be seen what they do when the new BEV platforms become available. To some extent it will depend on whether the new platforms will be less expensive to manufacture, and whether it is cheaper than the Kona/Niro. If they do stop making Kona, it won't be for lack of demand.
  8. wizziwig

    wizziwig Active Member

    Considering how difficult it is to get parts now (some people in Europe waited 3 months for a motor!), I would hate to think how rare the parts will become once they stop model production. I'm sure they will continue to produce the ICE versions of the Niro/Kona so no issues with the shared parts. More of a concern about the EV specific components on such a limited production model.

    Forgot to respond to this earlier. The Kona was actually the second case of a catastrophic motor failure. The first happened on a eNiro a long time ago. I had trouble finding the link again since most of the activity about these cars is on non-english forums. From what I recall, this one failed during a dealer test drive where the drive axle/shaft broke (difficult to know exact details due to language barrier). Prior to the failure, the car produced the clicking noise we're familiar with for a long time but continued to be used for test drives due to limited supply. Brief mention of it here. Same incident was also described on another Dutch forum but can't find the exact post.

    In that thread, owners also describe their motor replacement experience which matches what I saw elsewhere. New motor revision with some kind of reinforced plate to mate the gearbox to motor. This ends up requiring longer bolts and drive shaft.

    I will say that the quantity of posts complaining about this issue on various international forums has declined in the past few months. Not sure if this means newer cars are less frequently affected, warmer temperatures, or simply a side effect of nobody driving anywhere due to virus lockdown.

    Unfortunately, no decline in reports of dead 12V batteries. If anything those have actually increased.
    Last edited: May 23, 2020
  9. I would agree the warmer temps definitely have had an affect, as I can only make mine tap at will first thing in the morning while in reverse (about 10 to 12 degrees ambient C at that time). The rest of the time it is now silent.
    I am also not a big fan of having the inside of my car hosed down with alcohol, so I am waiting for both the software update and tapping noise investigation until things settle down.
    KiwiME likes this.
  10. wizziwig

    wizziwig Active Member

    Looks like owners in Korea are also suffering from this issue and have torn down the gearbox to investigate.

    Translated Blog Post.
  11. ericy

    ericy Active Member

    It isn't clear from the blog post what they think has failed, although they imply that replacing this isn't fixing the problem (one person replaced the "reducer" 4 times).

    And I am curious as to what kind of warranty they have there where the dealers don't replace these things at no cost to the customer. Normally we don't get to even see the thing. Although I wonder if what happened was that the dealer changed the part and let the customer have the old one.
  12. wizziwig

    wizziwig Active Member

    Unfortunately, I don't speak Korean so we're all guessing here. Based on the crude translations following that blog, there are multiple owners who had the gearbox replaced up to 4 times and the motor replaced up to 2 times. They acknowledged that the motor was eventually revised but don't say if the cases of multiple motor replacements used the original 700 or revised 701 motor design. Hopefully the new revision is not failing at such high rate.

    Due to the high number of successive gearbox failures, they were also hoping the gearbox would get revised. That's why they took it apart but unfortunately didn't find any changes. Makes sense since the part number didn't change.
  13. ericy

    ericy Active Member

    I guess I assumed that if I had a gearbox changed, that I would not be allowed to keep the old part. But this might be completely wrong.

    I hear no noises in my car, but if I did get into a position where they needed to start swapping parts, I would ask for the old ones. Worst case they just say no.
  14. If the replacement is a warranty issue and the cost covered by Hyundai, than they may require the old part retained by the dealer to be sent back as proof of replacement or for other reasons. Out of warranty is another ball game.
  15. ericy

    ericy Active Member

    That's kind of what I would have thought. Initially they probably wanted them back so they could analyze them, but at this point they no longer would need this. At some point the shipping cost to get the thing back would become a nuisance. Still - if it were me, I would ask.

    If I had the thing, I would make a long youtube video showing everything I could find about the thing - not only how the thing would normally operate, but look closely at what it was that failed (which I assume to be failed bearings), including looking a some of the surfaces under a microscope.

    I have seen youtube videos about the Bolt and Leaf reducer - not one yet for Hyundai/Kia.
  16. hobbit

    hobbit Active Member

    It sort of looks like the person holding the differential assembly might be
    emphasizing a lunched bearing on that; it's hard to tell what that slightly
    conical surface around the bearing rollers is but it doesn't look happy.
    The sleeve where the motor shaft would come in looks relatively okay...

  17. Those are tapered roller bearings so 'conical' is what they normally are :).
    Noting that this happens to be one of my few areas of professional expertise, the evidence I see is scoring of the motor-side input bearing location. So, the bearing outer raceway was spinning in the housing. The causes of that might be large debris entering the bearing, overloading, overheating or failure of the ball cage, noting however that the bearing is not discoloured from heat and the cage looks intact.

    It could be overloading due to the over-constrained phenomenum I mentioned back at post 141.
    The other possibility is debris entering from the parking pawl. To minimise that effect, best to always engage the EPB (parking brake) before taking your foot off the foot brake when shutting down. When you are ready to drive off just let the car automatically disengage the EPB. Just like a conventional automatic transmission, don't let the car's weight rest on the parking pawl when on a slope.

    Last edited: Jun 5, 2020
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  18. ericy

    ericy Active Member

    So if the bearing was spinning in the housing, it could probably explain the oil turning black, as the case is aluminum.
  19. Exactly ...
    It may initially spin only when under high torque in the first root cause scenario, or when debris enters in the second. The more it wears the easier it will spin and the dirtier the oil will get.
    The bearings for the first and intermediate shafts will likely be a slip fit in the housings to allow assembly of the case halves, so there's already a slight possibility to spin the outer with thick (cold) oil. That's a third option for a root-cause scenario that's been in the back of my mind for a while since I've noticed many cases seem to be reported from colder areas. Adding to that idea, the support of the input shaft from the motor (via the spline) may reduce the bearing's radial loading sufficiently to allow it to spin. This is a very plausible failure mode although it's unclear why the motor may have had a p/n change, nor how a motor design flaw would contribute to this.

    (As a note, the diff's tapered bearings have the outer raceways press-fitted into the housings, that's the normal fitting method for that type of bearing.)

    The colour of the oil (or better yet, the results of an oil analysis) is likely a very good indicator that the issue has started, even before a noise starts.
    Last edited: Jun 6, 2020
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  20. Excellent description and diagnosis, we are lucky here on this forum to have this input and thank you.:)
    Now to solve the problem, like properly seating and lubricating that bearing.
    Have you contacted Hyundai with any of this info, we could sure use your talents (perhaps assisting their engineering staff) with a resolution.
    I sure like my Kona EV, and this drive train issue is kind of (as been quoted before) "taking the shine off":(
    KiwiME likes this.

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