Repair issues and fixes

[R P]

So apparently the GRU itself did cause some of the noise?
Did the dealer give any explanation of the possible secondary failure mode? Perhaps there is a connection between 2 failures here:
How does the GRU failure lead to the Motor failure?

My understanding is that with the new motor came a stronger clamping mechanism for the motor and gearbox to eliminate potential fretting on the mating surfaces. When I first had just the reduction gearbox replaced the tech showed me the aluminum bits and shavings which to him indicated fretting.

I spoke about this several times in this forum regarding this issue early on. I don't have the Kona anymore, but after the motor replacement I put on another 30K kms with the issue not returning. I believe the new motor corrected it. Changing the oil (as I did initially) can't hurt but I don't believe that fixes or prevents the problem.

And I don't remember anyone having the issue again after both the gearbox and motor were replaced (in that order).

 

[coder]

Rp that is good info, thank you!
Maybe the causality here is the inverse of what we originally thought...
Perhaps the poor/lose coupling between the motor and GRU causes the accelerated wear of the GRU?

 

[coder]

As I recall the explanation on what he problem is or how to prevent it evolved over time:
At one point: They forgot to put a magnet on GRU drain plug. -> Use a Votex or Toyota plug, or stack some magnets on the plug.
Then we discovered that the GRU actually did have a magnet deep inside. Then we thought that the built in magnet was not properly fastened down, so it would rattle, hence not work (well). As per RP-s post, there is a problem with the GRU-Motor coupling.
Still trying to figure out how the loose coupling causes the wheel of fortune noise.
In any case, I think I will change the fluid once in a few weeks to see if it still gets black, then leave it alone, and hope for the best.

 

[coder]

Just checked, the dealer left off the skid plate (the lower engine compartment cover under the car). They tend to do this, it saves them 20 minutes.
OTOH if it is in place, it protects the engine compartment from road salt splash. Here in New England it matters.
Am I being unreasonable here?

 

[navguy12]

Just checked, the dealer left off the skid plate (the lower engine compartment cover under the car). They tend to do this, it saves them 20 minutes.
OTOH if it is in place, it protects the engine compartment from road salt splash. Here in New England it matters.
Am I being unreasonable here?

You are NOT being unreasonable.

I hate situations where I must hand over a vehicle to do a job that I no longer have the tools to do myself…when doing it yourself the job is invariably done correctly.

Including all push pin clips for aerodynamic shields.

Rant over.

 

[KiwiME]

Not at all, it's part of the car and is there for a reason.

... Still trying to figure out how the loose coupling causes the wheel of fortune noise.

I'd suggest that there's no need to waste your time, it doesn't. Despite a substantial number of Wof reports to date, no evidence has ever surfaced proving or even suggesting that the splined coupling was responsible for the WoF or doesn't work as it should. No description of the repair of a motor or GRU has ever mentioned having to replace the shafts that make up either side of that coupling. The presence of minor steel wear dust is not an indication of an abnormal condition. No part of that coupling is made from aluminium.

The revised bracket and longer bolts did raise eyebrows years ago but nothing has indicated that this was a solution. It's entirely plausible that in the "WoF TSB" meeting held at Hyundai-MOBIS headquarters, someone from the NVH (noise, vibrations and harshness) group raised their hand and suggested this as a potential fix while no one else had a better idea. Its inclusion has been more of an indication that they had not fully investigated the problem when the TSB was issued. The same disappointing rush to judgement saddled owners with the blue coolant, nearly as much of a maintenance annoyance.

... Then we thought that the built in magnet was not properly fastened down, so it would rattle, hence not work (well).

That multiple scenarios were considered and most rejected based on new evidence enhances rather than trivialises the scientific reasoning.

Not only does all the evidence point to the loose magnet as a root cause but there is even a smoking gun. Even after moderate miles the magnet remains clean.

It only has one job - to permanently sequester ferrous wear particles. That it completely fails to do that is not just a minor curiosity in the bigger picture but rather a fatal blow to the reliability of this design.

The Renault Zoe, 2010-2017 approx, an early EV nearly as popular as the Leaf outside of N. America, has the same problem - and a loose magnet. The Leaf has the same drivetrain design architecture as the others, but has fixed magnets and no WoF problems. The magnets are always founded loaded with metal as they should be.

 

[coder]

"Not only does all the evidence point to the loose magnet as a root cause but there is even a smoking gun. Even after moderate miles the magnet remains clean."

That makes perfect sense.
Yet if that was the answer, replacing the reduction gear should take care of this.
What I am stuck on, is why is that not enough? In my case, the dealer claims the WoF noise was still present after they did that.
Replacing the engine is rather expensive (just the part was ~6K USD), and I have a hard time believing they would
readily absorb that cost unless they had a reason. Thoughts?

 

[R P]

Problem I have with @KiwiME theory is that the WoF comes back after the gearbox replacement, and almost immediately. If the gearbox had been damaged, then the replacement should be good, at least for a while. But that is/was not the case as evidenced by many people. However, when the motor is replaced next with the revised clamping, the noise is gone, for good. Or at least have never heard of it coming back when the motor was replaced after the gearbox change. I know in my case it was fixed. That tells me, too, the sound issue damage could be actually in the motor, not the gearbox.

And as we know, too, changing the oil, and even early does not prevent the WoF noise from occurring. But the gearbox and motor replacement does prevent the sound from recurring. And as I have mentioned many times, my tech did find evidence of fretting when they examined the gearbox after the first occurrence. He showed it to me. My eyes don't lie. What more evidence do you need?

Another thing I should mention is that initially the sound was temperature dependent. When cold the sound would happen. But when the car warmed up with a bit of driving it would not. We know metal may expand or shrink with temperature, which then could affect the clamping pressure on the mating surfaces. And again, why did Hyundai change that with the new motor if that was not an issue?

 

[coder]

Sorry I am not a native English speaker. I have a vague sense what fretting may mean in this context, but not quite sure.

Something like: Loose coupling/backlash/play when one component can move to some extent before the other, coupled component
follows? I expect something like that would produce a more random clunking noise, not quite the WoF "orderly" clearly
RPM dependent noise. That has to be some rotating component tapping on something.

I noticed a temperature element in this puzzle. Louder noise when it is cold.
Also: less noise initially, after the car sat idle overnite. Not sure if it is because cold vs warm.

 

[R P]

Fretting is a common mechanical term when two clamped components may have some movement on the mating services. Initially the noise was only evident when the car had not been driven for a while (like overnight). Then after driving for a while, the noise was not present. It was not a random noise, but a very faint steady ticking at low speeds.

 

[KiwiME]

What I am stuck on, is why is that not enough? In my case, the dealer claims the WoF noise was still present after they did that.
Replacing the engine is rather expensive (just the part was ~6K USD), and I have a hard time believing they would
readily absorb that cost unless they had a reason. Thoughts?

Had you considered that your motor had failed while perhaps the GRU had not? Both failures fall under the same 'motor rumble' TSB procedure from both Hyundai and Kia. Owners of course also refer to both as the wheel of fortune.
It may have been diagnosed incorrectly, or both had failed. This mechanic went through the same process with a Niro. As to costs, I don't see that those should influence a technical opinion without a good understanding of their business process.

Yet if that was the answer, replacing the reduction gear should take care of this.

Are you assuming that the defect has been corrected? There has been zero indication of that within the last 6 months. Several owners with replaced GRUs have been keeping me apprised of their early oil changes and they're all seeing copious particles early on. A few owners are on their third GRU, two on their fourth.

As for the motor, there are indications that the newer revisions are far less likely to fail. Note that revisions have changed on the motor part number, not the bracket that holds it in place.

To reiterate, my research has been focused solely on the GRU and finding the most likely root cause for the failure of that part. I've looked briefly at the motor issue and although it's always been the tail-end bearing causing the noise, the reason for that is not proven. I found a design error with its axial (spring) preload being too low but don't have enough information to accept that this is the root cause. But there's nothing that owners can do anyway to mitigate a failure so it doesn't really matter what caused it. The preload would be easy enough for Hyundai to rectify and perhaps that's what they've done for later revisions.

Note that the TSB describes 'spinning' the motor shaft with a drill motor to detect a noise. There are a few videos online showing this process and an abnormal bearing noise is easily heard. Nowhere in the TSB does it say to inspect the condition of the spline.

What more evidence do you need?

Had you considered perhaps a few other owners with similar information? That hasn't happened despite well over 100 reports.

I spent months going down the rabbit hole of alignment and bearing layouts and in the end it did not pan out to something that could cause a GRU failure. See here and here for the gory details.

I've focused on and have considered all potential internal engineering defects and the ever-increasing evidence overwhelmingly pointed to the conclusion I've reached. Perhaps your spline did fail but there's no clear and consistent path as to how that could cause the GRU intermediate shaft bearings to fail, the most common items inside the GRU found in poor condition.

 

[R P]

I am not an engineer, but I can put 2 and 2 together. From what I know, there have not been any failures after both the gearbox and motor have been replaced in that order.

I have long since sold my Kona. Was my first BEV, and now I have two, no ICE cars. I did like my Kona, though, and thought it was an excellent car for what it was. If that tick tick is now solved, would be a good car to hang onto.

 

[coder]

Thanks Kiwi! Tons of good info, will read through later today.

On a different note, ever since they did the work, the car is making loud clanking noise every time I go over a bump.
Given that they left the splash shield off under the engine compartment, I wonder where else they cut some corners.
I wonder if there is a nut or 3 that was left off or un-tightened. The did never exhibited this particular symptom before they did the
3 part TSB.

Going back to the dealer's next Monday, in the meantime do you guys have any suggestions what I can check to diagnose what may be
causing this problem?

 

[coder]

It transpires, the mechanic who worked on my car simply has thrown away my splash guard, the dealer had to order a new one. They determined that a rubber bushing was damaged, along with some suspension part, when they worked on the reduction gear, which caused the clunking noise when driving over bumps. They fixed all that, so the car no longer has any objectionable noise.

Still, it is kind of disappointing that they don't bother to do a proper job unless the customer checks and insists.

 

[coder]

Ona different topic, my Kona EV is now > 5 years old, It think a break fluid flush is due. Anybody has a recommendation for fluid? I am thinking some high quality German Low viscosity fluid should be OK. Maybe ATE SL.6? Looks like a modern abs brake system, I do not see anything unusual.
Done this many times on other cars... is there anything unusual to watch out for (when flushing the brake fluid) ?

 

[KiwiME]

Apparently the kit a proper dealer uses applies a relatively high pressure around 50 psi to force new fluid through. I tried using my own low-pressure pump and didn’t work. I gave up after finding the fluid from the wheel closest to the master cylinder was clean anyway. It had been done 3 years earlier by the dealer.
I’d suggest either finding a better dealer and check that they have the right equipment or simply replacing the fluid in the reservoir, which is a substantial quantity.

 

[coder]

Huh, that is interesting... The kit I use is a vacuum bleeder. It attaches to the bleeder nipple on each of the wheels, and sucks the brake fluid out. Makes vacuum by spinning an impeller via compressed air. Or I have done it old-school, with an assistant.

 

[KiwiME]

On recollection I think I was using the vacuum method with some results. I'd proceed with caution as the very-expensive unit is nothing like a convention master-cylinder design. One owner here years ago triggered a dash warning when trying to 'pump-up' the pedal with power on and had to get the dealer to correct it.

Perhaps try the vacuum method and don't touch the pedal at all. You could even disconnect the 12V battery just in case it automatically reacts.

I'll also add there was a other report of "failed brakes", this time on Reddit. As usual a emotional post against Hyundai with no actionable details.

 

[coder]

Thanks for the heads-up.

 

[OzKona]

As I posted a page or two back, I had the GRU replaced under warranty due to WoF noise.

Not lucky, I'm afraid
Occasionally I can hear a slight moaning noise at speed which was present before the GRU was replaced. It was not there when the car was new and is too faint and hard to identify to make it worth reporting to the dealer. They would just test drive and report "Nothing found", I'm sure.

I changed the oil at 1000km. Black as the ace of spades with the same colloidal metal in suspension as per my post#225 on page 12. It's on its way to failure again, just a matter of time.

I don't think I want to keep the car any more. Will see what the dealer says, and may have to wait for more failures/attempts at rectification before commencing consumer action. Or sell it, with remaining warranty, suck up the $17000 loss it will cost me over my 2.5 years of ownership and get a 2023+ Niro. My son can lease one of those for me at very affordable fortnightly rates. Or I might get a mid-range EV6 for a few more $$.

With this drive train, plus the towbar issue, this car is not the right one for me.

The pic shows the colloidal metal in the oil:
View attachment 21643

With personal health issues and the loss of my wife since I posted this nearly 2 years ago, Kona matters slipped off the radar and I've kept the car.

It's now done 36k km, 30k of them on the oil change I did at 6k. I changed this oil out today. It was black, but not as black as the pics above, and with less colloidal metal observable.

I cannot detect any transmission noise, so I have decided to keep the car until the noise becomes evident. I have a year of warranty left. If it fails out side of warranty I will push for statutory warranty (Aussie consumer legislation that says goods must be fit for purpose and durable. If push came to shove, think I would have a case.) If I lose that battle I may trade it and lose a lot of money, or keep it and pay for a new GRU myself, losing less money than if I trade it. Depends on circumstances at the time.