Repair issues and fixes

[KiwiME]

Here's an attempt to make the gear oil analysis data easier to read. All (9) 'no-magnet-added' first oil change reports so far have been incorporated into the iron and aluminium trendlines. The actual trends are by no means expected to behave linearly with distance driven but the lines provide a visual average of the highly-scattered data. The line widths are intended to improve clarity only.

For the individual reports, all iron (Fe) datapoints are squares and all aluminium (Al) datapoints are hollow triangles. The iron and aluminium values are paired by owner and those pairs ordered in the list by increasing drain intervals, noting that this value won't be the same as the odometer reading for reports of 2nd oil changes. Since each owner's report is at fixed drain interval the two associated markers happen to be on the same vertical line, making them easier to match up.

The datapoints really are surprisingly scattered and comments made by the laboratories on some reports indicate that these are "high" to "very high" levels. I'll note however that many of these reports read like horoscopes and certainly these vendors want your repeat business.

For iron it may be a matter of whether the stock internal magnet has any effectiveness since any fresh wear particles captured won't show up in the numbers. With an owner-added magnetic plug (or equivalent disk magnets) we should see those levels plummet, as has happened at line #3.

For aluminium it's anyone's guess at this point because we don't know where it's coming from. A cleanly assembled gearbox working correctly should not be leaving aluminium debris as all normal wear parts are made of steel. The aluminium itself is not harmful, it's only a matter of why it's present.

It could represent either casting flash or machining debris left during production, or more concerning it could be unintended bearing outer-race spin causing wear in the aluminium housing. The only other reason I can think of is erosion damage from oil circulation as sometimes seen in ICE water pumps. The highest aluminium value from a Leaf gearbox [of the (2) Leaf UOAs I have as references] is 130 ppm at 20,000 km which is about double the trend below. The lowest is 36 at 107,000 km, a trivial amount.

A related item that's caught my attention recently is that very occasionally we see a first oil change that is almost clear but with some black particles. The example pictured below is after 72,000 km on a 2019, reported on FB. I'm beginning to think that it's mostly or entirely the aluminium content that discolours the oil while the iron content may not.

 

[rgthoma]

I replaced my gearbox fluid after reading this thread. I have a 2020 Kona Ultimate with about 4200 miles. I never noticed any noises prior to changing the gear oil but now I do! I hear the Wheel of Fortune but only at very low speeds, maybe 2-4 MPH and when braking slowly but not always. There is no noise if I use the paddle brake. I cannot reproduce the same noise as found in some of the YouTube videos at faster speeds. At least for right now, this is only happening at very slow speeds and when slowly braking at low speeds. I purchased this Kona a few months ago with just 200 miles on the odometer. I typically drive in ECO mode. I did place 2 magnets (not sure the exact size, maybe a US dime or so) on the drain plug and 1 on the fill plug. I did this about a month prior to changing the fluid. There was no noticeable deposits on either plug. I refilled with the Redline Oil 50604 MT-LV GL-4 Gear Oil. The fluid that was drained was not any different than what has been reported here. Dark in color with silvery-metallic tones very visible. I did struggle to put an entire quart in the gearbox during the refill. There was no way that I could see to add any more. The car was level during the drain and fill. Any ideas why the noise presented itself after the fluid change?

 

[electriceddy]

I replaced my gearbox fluid after reading this thread. I have a 2020 Kona Ultimate with about 4200 miles. I never noticed any noises prior to changing the gear oil but now I do! I hear the Wheel of Fortune but only at very low speeds, maybe 2-4 MPH and when braking slowly but not always. There is no noise if I use the paddle brake. I cannot reproduce the same noise as found in some of the YouTube videos at faster speeds. At least for right now, this is only happening at very slow speeds and when slowly braking at low speeds. I purchased this Kona a few months ago with just 200 miles on the odometer. I typically drive in ECO mode. I did place 2 magnets (not sure the exact size, maybe a US dime or so) on the drain plug and 1 on the fill plug. I did this about a month prior to changing the fluid. There was no noticeable deposits on either plug. I refilled with the Redline Oil 50604 MT-LV GL-4 Gear Oil. The fluid that was drained was not any different than what has been reported here. Dark in color with silvery-metallic tones very visible. I did struggle to put an entire quart in the gearbox during the refill. There was no way that I could see to add any more. The car was level during the drain and fill. Any ideas why the noise presented itself after the fluid change?

What ever the cause, time to get it to the dealer for the repair warranty process...

 

[KiwiME]

... Any ideas why the noise presented itself after the fluid change?

1 US qt (946 ml) should have been exactly what would be required to refill the gearbox. It's not going to be fussy about perhaps 100 ml either way but if you installed less than that you should correct it. Not having noticeable debris on the plugs + magnets after one month is not indicative of anything being out of place.

I'm wondering if you do have the actual WoF noise and not a brake noise since that's the speed when they're active on a flat surface? As you point out all the videos indicate the WoF noise happening at higher speeds while slowing down under regen. You could try slowing down from say 20 mph in Neutral as only the friction brakes come into play, regen is disabled.

If you do have a gearbox noise it's not going to be related to having a fluid change, it's just the luck of the draw. We have no idea what percentage of Konas suffer from this, nor exactly why it affects some and not others but the numbers are very small, I would estimate well under 1% of the fleet. Adding a magnetic plug and changing the oil is intended to correct the ineffective stock internal magnet. We don't know that it would also prevent onset of the WoF noise but if it did it would be most effective when done just off the showroom floor. Doing this later would have rapidly diminishing effectiveness as miles are added. Otherwise the benefit of adding a magnetic plug can be noticeably quieter operation over the service lifetime. Certainly operating with particle-laden oil is not good for any gearbox and the condition you've seen at 4200 miles would be highly concerning in an industrial setting, as noted in many of the used-oil reports.

If the noise is clearly noticeable best have the dealer look at it now, but otherwise perhaps wait until the first service. Best remove the magnets before you take it in and only use them on the fill plug subsequently so you can reach them from under the hood.

 

[rgthoma]

Thank you for the information. I read the TSB that you provided and it states something about listening for the noise starting at 25-50 MPH. I think I will wait until the noise either worsens or at least becomes much more noticeable because I think my slow speeds could potentially limit what the dealer could do under the TSB instructions. I will try to brake in Neutral and see what happens. My wife is driving it this week to work and back so I most likely won't be able to try until next weekend. The noise that I am experiencing is much softer or quieter than what I have heard on the videos but the same type of noise nonetheless. I agree with your suggestion to remove the magnets prior to taking it in for service. Thanks again for the help.

 

[rgthoma]

I tried the braking in neutral method and found no noise when doing this. I believe this confirms the noise is related to the gearbox. Unfortunately, the noise still only presents itself at very low speeds and mostly when braking. Because the TSB states to drive 25-50 MPH to determine if the noise is present, I will wait until it gets worse, if it ever gets worse. The car came with the full 10 year/100,000 mile warranty so I should be ok for the next several years. Thanks again to everyone for your help and insight.

 

[electriceddy]

"Charge door open" message will result in multiple beeps and warnings when the door closed sensor is defective. By removing "Charger 1" fuse (10A) in the motor compartment fuse box, the beeps and warning message can be eliminated, and the car will still charge normally - without the ring light and charging horizontal bars. This is a band-aid fix of course, until a new charge port assembly can be installed. More info here starting at post #8 and the next few posts after that

 

[alphayash]

"Charge door open" message will result in multiple beeps and warnings when the door closed sensor is defective. By removing "Charger 1" fuse (10A) in the motor compartment fuse box, the beeps and warning message can be eliminated, and the car will still charge normally - without the ring light and charging horizontal bars. This is a band-aid fix of course, until a new charge port assembly can be installed. More info here starting at post #8 and the next few posts after that

Thanks for the info these multiple beeps and warning were irritating me a lot. Now I can fix it, though temporary but atleast a solution.

 

[alphayash]

Thanks for the info these multiple beeps and warning were irritating me a lot. Now I can fix it, though temporary but atleast a solution.

No reply to this.?

 

[KiwiME]

We've had a few more used oil reports show up so I'll post the latest graph which includes a new change interval with the benefit of owner-added magnetic plugs. As expected the iron value is much lower as a result while aluminum is more or less still average. As before the two trendlines are based only on data with no owner-added magnets so that we can try to identify any improvements made when magnets are used.

There has been renewed interest on both FaceBook and Reddit on both this issue and the tapping noise, which seem to still be confused as being interconnected. I'm reminding owners that based on all available evidence their chances of acquiring the tapping noise seems to be entirely random. The benefit of doing an oil change and adding a magnetic plug is more to ensure that the actual quality of gearbox lubrication matches what the owner's manual calls out, that is clear, clean 70W oil, not blackened and full of metal particles. That's all an owner can do to minimise the chances of needing warranty work and enjoy quiet driving.

Speaking of that, the recent quietness in this forum and all the other Kona forums seems to suggest that this model is reaching mid-life where owners are done with early questions and issues, and the very few serious issues we had have been mostly resolved. Additionally, some owners have moved on to new EVs such as the Ioniq 5 and EV6.

We had a report today on FB of a Kona EV reaching 230,000 kms (~144k miles) in an unidentified country. The owner didn't say if the battery had been replaced under the recall (despite my prompt) but I did request the BMS 'coulomb counter' values which were provided. Based on that, the battery had accumulated 412 full-charge cycles, returned an average pack-to-wheels efficiency of 12 kWh/100km at an average speed of 32 km/h. The latter numbers suggest that it might be used as a taxi/uber or similar city-only use. The SoH stated by the owner was 98.6% and the cell balance was still excellent.

The other item that can be derived from the BMS info is the historic average pack cycle efficiency which comes out as 95.5%. I can't be sure that this is accurate because small errors in measurement will accumulate. For interest, a new pack would be 98%, meaning 1% is lost on charging and 1% on discharging. It is expected that internal resistance increases with age and so losses would increase respectively.

Lastly, there's been one minor issue reported that owners should be aware of. We already know that the chrome cargo hooks on the trunk floor are just plastic and easily broken. Well, it's been found that the lugs that support the cargo cover on each side can also be broken if perhaps the hatch cover is slammed shut when the cargo cover is prevented from resting in the horizontal position.

 

[Ferenc Jakab]

Thanks KiwiME! useful and informative as always.

 

[hobbit]

The Prius community seemed to follow a similar arc, where a "standard" body of knowledge had
developed and incoming newbies were frequently referred to older posts and threads for their
answers. And the first few cars to achieve impressively high miles were mostly taxis or other
for-hire that were basically driving all day every day.

_H*

 

[Ferenc Jakab]

The Prius community seemed to follow a similar arc, where a "standard" body of knowledge had
developed and incoming newbies were frequently referred to older posts and threads for their
answers. And the first few cars to achieve impressively high miles were mostly taxis or other
for-hire that were basically driving all day every day.

_H*

And those were Nicad batteries in those models. Often went 600,000Kms. Still visit PriusChat occasionally.

 

[rgthoma]

I tried the braking in neutral method and found no noise when doing this. I believe this confirms the noise is related to the gearbox. Unfortunately, the noise still only presents itself at very low speeds and mostly when braking. Because the TSB states to drive 25-50 MPH to determine if the noise is present, I will wait until it gets worse, if it ever gets worse. The car came with the full 10 year/100,000 mile warranty so I should be ok for the next several years. Thanks again to everyone for your help and insight.

**Just wanted to provide an update. I took the car in to the dealer for the 5000 mile service and mentioned the "wheel of fortune" noise. The dealer seemingly went through the normal protocol of replacing the brackets first before diagnosing the traction motor. I got a call yesterday indicating the traction motor needs to be replaced but that particular part in on backorder with no ETA. So Hyundai is offering a rental car through a national chain but does not cover the entire cost. Apparently Hyundai covers $44/day and the daily cost through their authorized rental company is $45/day. Oh and a car isn't available until next week! Wow! It will be curious to see how long this takes to get repaired. I believe the lemon laws in my state say that repairs should be made within 30 days. Of course the current supply chain issues might come into play I suppose. I like the car but certainly don't like paying for the car loan, plus a very small fraction of the loaner car, plus the fuel while the EV sits waiting for parts.

 

[KiwiME]

I carried out an oil change on my Kona this week at 24,000 km, just 4,000 gentle kilometres since the last. Technically this is the third oil change despite intermediate inspections of the 1st and 2nd changes. Unexpectedly the oil was pitch-black with a faint sign of glitter. The magnets had been cleared only 1,000 km before and had nothing much added.

As I've said many times, in general engineering terms it's inconceivable that a simple single-speed gearbox could be turning the oil black over such a short period of use, where no indication of oxidation is present in the analyses.

To cut to the chase I think I'm closer to finding the culprit. There just aren't that many reasons why this could happen but there's one thing that's been bugging me for months and that's the discrepancy between @hobbit's Kona magnet photo and one from a Polish Ioniq owner at Ioniqforum.com who rebuilt his gearbox. @hobbit's photo clearly shows rounded edges not present in the Ioniq photo. Ceramic disk magnets are normally cylindrical in shape, sometimes with a hole in the centre as it appears to have in both photos. I've never seen one shaped like a piece of candy.

The disk magnet is captive in what I'm calling a 'dog kennel' feature in one half of the casting and a lug on the other half contacting the disk at the edge. The magnet will be captive only loosely by design because the casting process is not precise enough to hold it firmly without the risk of cracking.

The problem here is that the oil thrown off the final drive gear at-speed impinges directly on this area from above. Since the exposed part of the magnet is asymmetrical left to right there will be an off-centre downward force imposed on the magnet's top surface. There's little chance that it won't spin and rattle around.

Despite the oil bath that combined rotational and rocking motion may be wearing the magnet edges down along with the aluminium housing lug where contact is made. Google tells me that the composition of a ceramic magnet is "strontium carbonate and iron oxide". Furthermore "strontium carbonate is a white, odorless, tasteless powder" with very low "magnetic susceptibility".

I'm suggesting that the wear producing both iron oxide and aluminium could be the reason for the black oil, the high aluminium and at least part of the iron contamination.

The challenges ahead are how to prove this and mitigate the ongoing problem. Clearly if the magnet was to wear down far enough to escape captivity the outcome would be disastrous.

First, I have a small camera that I think I can use to view my magnet via the drain hole. That might confirm if my Kona magnet shows wear.

Second, it might be possible to detect certain motion of the magnet while driving using a coil of wire placed on the gearbox housing under the magnet, hooked to an oscilloscope or signal amplifier of some description. I have mocked this up on the bench and I can easily detect the rocking motion of a similar-type magnet at the required distance. But because the magnetic field will be axisymmetric I won't expect to be able to detect any spinning motion.

As for mitigation the only practical idea I have is to place a large-ish magnet underneath the gearbox to pull the disk magnet down. It won't stop it from turning but may add enough friction to reduce the ease of it doing that.

Here is the 4,000 km oil, the new oil and a Krombacher Pils.






@hobbit's photo:

 

[electriceddy]

composition of a ceramic magnet is "strontium carbonate and iron oxide

Well it's funny you wrote this, just as I completed my "GRU oil change kit" in preparation for 2nd year service on Friday. I prepped them by gluing to the plugs and each other with JB Weld, and a coat of black paint (not on the threads). Kit also contains new crush washers.

Maybe the iron in the Neodymium (ferromagnet) external magnets will perform better. I am also having the brakes serviced, although it's still a bit early for a brake fluid change at this time. I also will be changing the cabin air filter tomorrow.

 

[KiwiME]

The plan of action I have is to mount the coil of wire pictured below under the gearbox (yellow outline) as close to the OEM magnet as possible. I have to come up with a bracket of some sort, as rigid as possible.

Any tilting or translation movement by the OEM magnet while driving will result in a tiny current being generated which will be displayed on the oscilloscope.

If I can establish that there is movement the next step is to attach a bar magnet to the underside (at the black rectangle) in an attempt to hold the OEM magnet in place. I have some on order that will be here in 2 days. The coil will still reveal any continuing movement because the bar magnet's field is static.

 

[KiwiME]

The mystery thickens!

I gave up on the coil idea because (a) it was just too huge and (b) I realised that it couldn't tell me the location of a magnet, only when a magnetic field is changing. Luckily a local electronics chain shop (Jaycar) stocked a specialised sensitive Hall-effect sensor that looks like it's perfect for the job. It will indicate when a static magnetic field is present and the rate-of-change of that will tell me when the field is changing. It's small enough to be glued or doubled-sided-taped in place when the time comes for that.

But when I probed around the underside of the gearbox I got a huge surprise. There was no magnet where I expected one to be from the photos we've seen. However a few centimetres closer to the drain plug was a very strong magnetic field, so strong it had to be a neodymium type. I spent some time trying to nail down the exact location which I marked, and determined that the pole facing me was "south". I also checked that it wasn't a stray field coming off the motor, Votex magnetic plugs or other nearby components. No, the strong field was limited to a small area surrounding the mark I had made, within a 1 cm radius approximately.

Then I thought I would see if a neodymium bar magnet 3cm x 1cm x 3mm would be attracted or repelled. It certainly did both, but I could not find a consistent pattern. Both attraction and repulsion seemed present and moderately strong as I flipped the magnet back and forth to present each pole to the gearbox. I also 'listened' using a length of plastic tube as a stethoscope but couldn't hear anything rattling.

Then I checked it again with my Hall sensor and "lo and behold" the magnetic field inside the gearbox had flipped poles! I was now seeing a north pole close to where there had been a south pole. For a moment I thought I had demagnetised it! Then, if on cue, a short symphony of precise-sounding clicks and whirs occured as the Kona decided it was a good time to do a 12V charge event.

So, I have some evidence now that my gearbox (a) does contain a strong magnet rather than a weak ceramic disc, and (b) that it can move.

My next step is to develop a circuit to support the sensor electrically and an in-cabin monitoring means to observe changes in the magnetic field while driving. I need the circuit to provide an electrically-robust signal to some sort of visual indication that I can check safely.

Regarding the inspection video camera, I tested it with a 45° mirror placed at the end as required to peer into the gearbox sideways and the picture is pretty bad, not really good enough to prioritise that task, especially given that I would have to drain the oil.

It will take me a week or more to design and build the parts I need so I'm putting the underside panel back on for now.

 

[electriceddy]

So, I have some evidence now that my gearbox (a) does contain a strong magnet rather than a weak ceramic disc, and (b) that it can move.

Interesting, possibly another contributor to GRU clicking (magnet munching) if that is indeed the case (not to mention iron deposits in the fluid).
I do have some extra neodymium magnets I could JB weld to the bottom of the case to prevent movement (by pole attraction), but with my luck, I would likely position the external magnets to repel and possibly cause an issue.
BTW your car underneath in all your pictures is exceptionally clean, showroom quality. Do you clean it when the cover is removed?

 

[KiwiME]

Well, the upper half of the gearbox is a bit corroded. I don’t clean anything except the splash guard. It’s just not that wet and muddy here.
So, my longer term plan was to encourage the magnet not to turn using a magnet attached to the underside. I had purchased some nice rectangular ones that would fit the expected location of the magnet. When I tried one at the actual more-spacious location it didn’t match well magnetically. However after some bench testing I think that’s due to the rectangular shape. I’ll try a round magnet on the gearbox and see if that’s better when I get back home. I’m in the ICE tonight, Kona is still up on the ramps.