Kona, Niro, (original) Ioniq and Soul will benefit from a gear oil change

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KiwiME

Member
Joined
Dec 12, 2021
Messages
15
Location
New Zealand
A couple of us Kona owners have been working over the last two months to rectify a choice by Hyundai to not provide basic ferrous particle filtration in the gear reducer, or what everyone knows as a magnetic drain plug. All the Hyundai/Kia cars I've listed in the subject line I believe use the same family of gearboxes or even the exact same model as the Kona. It's a splash-lubricated 2-stage parallel shaft single-speed reducer with helical gears - that happens to be identical to the type used in the Nissan Leaf, hence the post in this forum. It runs a 70W/75W GL-4 such as Redline MT-LV, rather than an ATF.

Due to this inexplicable omission steel particles shed during break-in and from ongoing wear continually circulate among the gears and bearings until they have been ground down to a fine dust. This makes the oil look black like black coffee. For those not aware, rolling element bearings deteriorate faster when ingesting steel particles. Gears are less fussy but it's never a good thing.

So, our earliest oil change was done at 3,700 km and it was black with silver particles. We have reports of perhaps six more oil changes up to perhaps 80,000 km, and of course all were pitch black.

The simplest and cheapest preventative measure any owner can take is get ONE oil change ASAP before the callout in the maintenance schedule, typically 120,000 km. That will reduce the rate of ongoing wear from that point on and may lessen the chances of a failure outside of warranty. As many of us Kona/Niro owners know, there have been many gearbox noise complaints and a couple of documented catastrophic failures where the output shaft (diff) tapered-rollers fail.

The ideal situation is to install a magnetic drain plug (or 2 as used in the Leaf) when the car is new so that break-in particles can be sequestered up-front. Once these particles are ground down they have less affinity for the magnet and the damage has already been done. We are testing an aftermarket plug with a glued magnetic but I'd be cautious about recommending this one until I've had a few months more experience. There are others, some with a crimped-in magnet (like the Leaf) but they need to be short, not sticking out like on the Leaf. The thread is M18x1.5 and the thread length is 12mm. You could have 3mm more for the magnet to stick out. The washer is soft aluminium, 1.5 or 2mm thick.

We also have two oil analyses but there's nothing unexpected except the high aluminium and silicon levels, much as seen in the Leaf Blackstone reports posted elsewhere. The aluminium is a concern because of where that could come from, the primary and intermediate shaft bearing retaining diameters.

I'm an M.E. and have some industrial gearbox experience from long ago. I'm quite aware that these gear reducers can survive with oil in a deteriorated state but I'm puzzled that Hyundai/Kia would have taken such a risk when every other EV manufacturer seems to have done it right.
 
Good post. I saw your https://bobistheoilguy.com/forums/threads/uoa-for-hyundai-kona-electric-high-aluminium-and-silicon-levels.348730/ too.

Yes, most of that silicon element you see is anti-foam, very important. Some of it might be from some ground-up gasket material, no problem. (In engines, high silicon is a sign sand dust is getting in past the air filter area, yet a gearbox like a Kona or Leaf probably doesn't have that issue.)

The Kona EV 70W GL-4 has about the same viscosity as the Nissan Matic S ATF fluid in the Leaf. The much higher levels of anti-wear phosphorus in the 70W GL-4 stuff makes it a better oil to use than the Matic S brew with low levels of anti-wear chemicals. I'll probably get the 70W GL-4 fluid into my Leaf eventually.

My Leaf's (22 SV+) original fluid is in there now, at only 500 miles so far. First I'll put in Valvoline Maxlife ATF, the right viscosity, and with twice the phosphorus as Matic S. After a few thousand miles more I'll probably change it to the Kona EV 70W GL-4 or maybe try Redline MT-LV with the much higher anti-wear levels.
 
Interesting to know... if all goes according to plan, I'll be a leasing a Niro EV from a dealer in So Cal (via an auto broker) this weekend then driving it back to Nor Cal. I probably won't purchase at lease end but if I ever buy a used HyunKia EV, I guess I'd want to gets its gearbox oil changed pronto.
 
I just changed the almost-new (518 miles) '22 SV+ Leaf fluid out, and it is kinda surprising. Gears like this don't typically get the surface roughness already polished down completely at the parts factory. It "wears in", while in service, and we hope the magnets catch most of it. .... I ran across an Eaton co. patent the other day ( https://patents.google.com/patent/DE60130835T2/en ) which said the Ra (RMS peaks/valleys asperities roughness) should be between about 3 microinches to 10, ideally.

I can't figure out why Kia/Hyundai doesn't put in factory-installed magnets either. It does seem to help a lot. Cascading wear due to loose iron particles just keep grinding down the gear teeth & bearings. Tesla puts a magnet & even an oil filter on many of their later models to really get the most life and also to prevent warranty claims.

I put in Valvoline Maxlife ATF (kv100 5.9 cSt) for now, and will change it again a few months from now for it's final fill of Redline (mostly PAO/POE) MT-LV 70W GL-4 which includes a lot of phosphorus anti-wear chemicals in a proven formula for non-hypoid racing & street gear sets such as manual transmissions, DCT's, AMT's, transfer cases, etc.

prDugfh.jpeg
 
Thanks for sharing the photos and your findings. I am sorry for being a little slow but can't decipher if the photos are looking good or bad. Can you kindly comment on this? Did you find more or less particles on the magnets compared to what you expected to see? Thank you
 
It is more iron goop than I expected. With only 518 miles, I wasn't sure how they would look. It is probably par for the course though.

Turns out experts like Molakule on bobistheoilguy.com and a few other sources are probably right when they say you should change out the fluid at 500 miles when new to get out the initial break-in junk. .... If you want extra life out of the gears, bearings, and differential in there.

As far as the lack of magnets in a Kia-Hyundai gearbox, its strange since most engineers use magnets for these in other makes. For example, the Chevy Bolt has an internal magnet inside. Most ICE vehicle auto trannies have a sump magnet.
 
Maybe Kia use an internal magnet somewhere in the case, deeming it sufficient for the life of the vehicle?
 
Nubo good point. The way Kiwi_ME and others refer to the "black coffee" colored fluid after some miles, it makes one think nothing is in there cleaning up at least a portion of the iron particles.

For Kia-Hyundai EVs, I noticed a magnetic drain plug can be had from Porsche cars, Miatas, probably others, in the right size for those Korean EVs. ... M18x1.5 and 12 mm long plugs for differentials and manual trannies are out there.
https://www.autohausaz.com/pn/10607
https://drainplugmagnets.com/thread_type/metric/ I've used Dimple for ICE engine sumps, very powerful magnet.
 
I had a chance to see a soul gear box disassembled. There was a magnet installed internally. About 1 cm by 3 or 4 cm by 2.5 cm?
A little pocket cast in the bottom of the housing. Magnet slides in. When the other half of the housing is assembled, the magnet can't get out. Looking at that housing. I don't think a magnetic drain or fill plug would help. Drain and fill plug both at least 2 inches buried down a hole. No oil flow at all.
 
OK, the Soul Magnet (sounds like a good rock band name...) is like what the Bolt does, a magnet tucked away. Drain & fill pllug magnets would still collect more Fe particles since all the flow nearby would settle fresh fluid in there after driving around a while, slowly gathering at least something over the life.
 
Thanks for the interest in my post. I popped by today because there have been some developments.

The latest news is that an Ioniq owner in Poland had to rebuild his gearbox due to noises and found bearing degradation. He also posted internal photos of the gearbox. As clear as day there is a ceramic magnet captured in the casing halves at the bottom of the sump. So, at least I know the designers aren't complete idiots.

But here's the kicker - it was reported by the owner that the magnet was clear of ferrous debris but the oil was black. The failed bearings were said to be "sticky", specifically those on the intermediate shaft.

And this is why I'm looking to hear some Leaf expertise: The Leaf gearbox has one item that the Hyundai/Kia doesn't - a grounding brush on the intermediate shaft. The Hyundai/Kia motor has a carbon brush on the motor shaft as it exits the drive-end bearing, nothing else.

So, here's the question: why is the Leaf ground brush on the intermediate shaft instead of the input shaft?
 
Looking at the drains over in the leaf oil changes. The fluid looks about the same. Maybe a change early for the leaf would not hurt. I have seen ptus with dark oil like that with low miles also. Usually heat related. I don't think the leaf gets that hot though.
 
Oil color is not a good indicator of wear particles. An oil analysis tells the tale. Swapping out oil once early in the life of the car is easy enough in a LEAF, and hopefully so for Kia// owners that I would say anybody who bothers to ask the question should just do it.

As for the work involved in identifying and finding compatible extra magnets, I'd personally want an oil analysis to point me in that direction.
 
I'm all for the efficiency gains of using the lower viscosity fluid but I don't think I've ever heard of a single EV that failed due to a worn out transmission.
 
KiwiME said:
...
So, here's the question: why is the Leaf ground brush on the intermediate shaft instead of the input shaft?

i would guess that it is easier to access the end of the i/m shaft versus right at the motor shaft, and as long as they are grounded to the same potential it doesn't matter

Plus it might be that more components are in the ground path to bleed off any stray charge or induced fields or eddy currents. Not sure how effective it is with bearings and oil films in the path.
 
I would expect the intermediate shaft to be the most insulated part of the gear train during operation, due to oil films. But I'd also expect stray currents to be handled first close to the source to reduce risk to the input shaft bearings. As I mentioned the Hyundai/Kia motor has a circular conductive brush on the output shaft but none at any other location as best as I can make out. Does anyone know if the Leaf motor has one?

Our three Kona UOA indicate:
kms / Fe / Al / Si / Ca / Zn / ISO
3700 / 95 / 46 / 50 / 2293 / 1760 / ISO: 24-21-14 /
15,600 / 195 / 145 / 65 / 2554 / 1488 / ISO:23-23-20 / 4u = 49892, 6u = 42956, 14u = 9204, 21u = 380, 38u = 22, 50u = 16
28,000 / 205 / 283 / 64 / 2635 / 1371

Essential data from two Leafs posted elsewhere on the forum, for comparison:
kms / Fe / Al / Si
20,090 / 91 / 130 / 63
107,870 / 120 / 36 / 34
 
Well, the good news is, here in N. America at least (don't know about New Zealand, kiwiME...), Kia & Hyundai have a long 10 year / 100,000 mile (160,000 km) in case the gearbox starts making strange noises.

@KIwiME , Could it be possible Kia-Hyundai did not harden the gear wear surfaces and/or bearings in there enough? Lack of proper carbonitriding has caused a Ford Focus EV gearbox recall in my own experience, and I've heard of that problem popping up on some (VW?) cam surfaces in valvetrains.

Its easy to change the fluid on a Leaf, so I can do it just for fun at home really.
I will sort of copy what Hyundai-Kia specs with their GL-4 70W/75W at about 6 cSt (Mine will be Redline MT-LV all-POA at a similar 6.5 cSt kv100). GL-4 has more phosphorus for anti-wear than ATF (Matic S, Dex VI, etc) fluid does.
 
As I mentioned above I'm leaning towards shaft eddy currents being the root cause because if the single grounding brushed ring fails to work effectively the gearbox will deteriorate without leaving debris. A gear wear problem would result in metal debris.

In most countries, 96% of the global population, Hyundai/Kia only offer a 3 or 5 year warranty like many other brands. We did not suffer the Excel so they don't have to beg. My Kona EV warranty expired Oct 2021 with the exception of the battery which runs for another 5 years. It's in my best interest that the gearbox doesn't fail.

https://youtu.be/aAsG6SEQ8Qs
 
KiwiME said:
As I mentioned above I'm leaning towards shaft eddy currents being the root cause
Earlier Teslas had that problem, I think it's similar(??). Somebody else on this forum told me about it, and I googled it a bit to get the story. Anyway, if you're interested, google terms: tesla bearing failure ceramic milling noises

Ceramic bearings are not conductive, allowing current to bypass the wear surfaces, if I understand that right.
 
To bring this subject up to date we have (11) first-change used-oil analysis results now and the data is very scattered with many indicating high iron and aluminium levels at a low drain interval. The averages take aluminium from zero to 200 ppm and iron from 120 to 200 ppm, both over drain intervals ranging between 4,000 to 60,000 km. I'd post a photo if this forum hosted that, sorry.

We know now that there is a factory-installed captive ceramic magnet but our UOA results indicate that it's not effective. Also, one brave owner pushed a paperclip inside and it wouldn't stick. The addition of an aftermarket magnet plug seems to work well at bringing iron levels down according to (2) recent UOA results at short drain intervals.

Out of about 40 total oil changes (Kona and Niro) reported in owner forums we have also seen that in a very few cases the oil is still clear but with some visible particles. Perhaps 5 or 10% of cases at a guess.

Personally I've done changes at 19,400, 19,500 and 23,600 km. The second was intended as a flush. For my most recent, a drain interval of only 4,000 km, it's turned completely opaque (black) with a small amount of visible sparklies. The (2) added magnetic plugs contained very little debris. Ongoing, my plan is to change the oil every 5,000 km but for owners who drive more I'm going to suggest a longer distance to be more practical.

Lastly, I still read about owners reporting drivetrain noises about once every two weeks. This first shows up as a tapping noise, usually only when decelerating. There is a TSB on the subject from both Hyundai and Kia and those revolve around determining which item (motor or gearbox) is making the noise and how to replace that. The condition of the gear oil is never questioned.

Those are the facts, now on to speculation.

I'm beginning to think that it's only the aluminium contamination that makes the oil opaque as we see now that the added magnetic plug doesn't stop that from happening.

Additionally we have two photos of the factory magnet and in one (a classic Ioniq) it appears shaped as a cylinder with a central hole, a typical ceramic magnet. In the other photo (a Kona) it appears to be worn at the edges like a piece of candy. I'm wondering if the magnet is spinning or rattling in captivity and that's wearing the edges and producing some of the contamination?

It's still unknown if the tapping noise is related to dirty oil. I'm leaning more towards a random misalignment of the motor and gearbox, noting that the design is very similar to the Leaf and both parts are typically found damaged. But for an automaker this seems to be a highly-unlikely mistake. It's basic engineering and production technology to get this stuff right, as Nissan did.
 
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