Gear Reduction Oil Change

Obviously there has been a lot brought up about this, especially concerning the change intervals.

I would like to add in conjunction with particle effects there is a more common form of contamination and performance reduction that being high humidity.
Thanks to VW Technician @ ID4 forum
"EV propulsion units are completely different than, ICE transmission.
It is more similar to the RWD differential, with some different parts like..... bearings ( balls are ceramic coated or use special non conducive metals to prevent arcing from eddy currents), slightly different oil chemistry that is tailored for electric propulsion units ( low conductivity).
One thing that will affect oil in this type of propulsion units are humidity ( it will cause acidity with time if vehicle was constantly used for short periods of time in high humidity or big temperature swings)."
Further couple of documents:

"Locations with high humidity or high altitudes can create unique problems for shaft mount reducers. Humidity causes condensation – even within a well-sealed gear reducer. When condensation (water) gets into your oil, it doesn’t work as well. To combat humidity, inspect the lubricant often and change it if necessary."
Also:
"Humid environments, or applications that see wide temperature swings, can cause condensation inside of your gear reducer, adding water to the oil. Any contamination will decrease the effectiveness of your oil. It’s important to check the quality regularly and change the oil if it’s contaminated."

I only brought this up to make owners aware that living in a high humidity environment is another good reason to replace the GRU oil before the indicated interval. I don't believe anyone has posted water contamination levels analyzed to this point.
 
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So, the specified 70W oil for the Soul/Ioniq/Kona/Niro is normally used in Hyundai's dual-clutch automatic. All other EVs including all later Hyundai/Kia use an ATF. I haven't seen any gear oil indicate that it's "low conductivity". The gear reducer has a vent at the top. I'm not aware that any are "sealed" and I don't think that would be good design practice.

I had a look through all the used-oil lab reports I have copies of, more than 10, and all indicate that water content was tested with the highest one being 0.16%. Most were zero, two were 0.1%. In the accompanying notes to each report, water content was not mentioned as an issue. The reports are from Australia, New Zealand, Canada and the continental US, possibly not the most humid parts of the world.
 
I finally did the GRO change on 9/16/23 and took a sample to send off to Blackstone Labs. We bought our Kona new in August 2019 and this is the first time that I've changed the gear oil. We've had no symptoms at all (~28,000 miles), knock on wood. Refilled with just shy of 1 quart of Redline MT-LV 70W/75W GL-4 and replaced the OEM drain and fill bolts with the Votex M18 x 1.5MM Magnetic Drain Plug (DP007) and new crush washers. Found the entire process to be very simple once I had the parts, and a syringe filler.

Did not notice any unusual color, sheen, or particulate matter in the old oil, nor did it have any noticeable smell other than what I would describe as "oil". Color was dark and oil felt viscus to the touch.

Blackstone Labs emailed results today and I wanted to add another data point to the running tally. I also wanted to get this group's thoughts on the results. See anything that should give me any concern? I'm thinking I will do a second oil change in another 10,000 miles and send that sample off for another test to compare with this first one.
 

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Thanks for posting that. Here's the graph updated with your iron (Fe) and aluminium (Al) levels in the red circles at 44,995 km, equivalent to the miles on the document. As you can see the iron (the square markers) is above the trendline representing the average. Aluminium (the triangular markers) is slightly under the trendline. But noting that all the data is widely scattered, there's really nothing unexpected.

Most have reported the oil black but you've mentioned it was not an unusual colour? Originally it was clear brown, much like the Redline you've installed.

* * * *
I'm pretty sure that the infamous noise problems result primarily in those few cases in which wear particles from the normal gear-tooth break-in process (< 2,000 miles) circulate and just happen to cause enough bearing damage to shorten the bearing lifespan to less than what's needed. This of course shows up as the wheel-of-fortune noise.

Fresh wear particles are supposed to be sequestered within minutes by a fixed magnet while they are large and easily captured. Locating the magnet directly in a major oil flow area (as it is) improves the chances. However in this design the magnet was left loose and scrapes off anything captured as it wobbles around in its pocket, partly due to being in the high-flow location that was supposed to improve its performance.

Returned to circulation, iron particles lose their magnetic attraction as they are further 'mechanically worked' (crushed) and so the opportunity for sequestration is quickly lost. Many DIYers have noticed that placing a magnet in the used oil doesn't attract much.

This is why I encourage a very early oil change, to do the job the magnet is not doing.

Without refreshed oil, aside from bearing damage, particles continue to wear down through about 15,000 miles. Eventually they are no longer visible and can only be detected by lab tests. Many lab reports include a particle count for those over a certain size. A test done early on will have a high particle count and low iron PPM values, while later on the opposite is the case. The aluminium seems to be a side effect of this process, perhaps coming from the the surfaces the magnet is rubbing against.

* * * *
Reports of noise problems are showing up about twice a week in the small number of global forums I follow, mostly on 2019 vehicles but I think that's only because they are more likely to have higher miles. There doesn't seem to be any 'safe' miles where once you get past that the problem won't occur. We have two cases currently in NZ that are out of warranty, but much to my relief it's been reported by both owners that our importer is starting the repair process on a goodwill basis.

UOA.webp
Hi-res image is at this link.
 
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KiwiME said:
Thanks for posting that. Here's the graph updated with your iron (Fe) and aluminium (Al) levels in the red circles at 44,995 km, equivalent to the miles on the document. As you can see the iron (the square markers) is above the trendline representing the average. Aluminium (the triangular markers) is slightly under the trendline. But noting that all the data is widely scattered, there's really nothing unexpected.

Most have reported the oil black but you've mentioned it was not an unusual colour? Originally it was clear brown, much like the Redline you've installed.

* * * *
I'm pretty sure that the infamous noise problems result primarily in those few cases in which wear particles from the normal gear-tooth break-in process (< 2,000 miles) circulate and just happen to cause enough bearing damage to shorten the bearing lifespan to less than what's needed. This of course shows up as the wheel-of-fortune noise.

Fresh wear particles are supposed to be sequestered within minutes by a fixed magnet while they are large and easily captured. Locating the magnet directly in a major oil flow area (as it is) improves the chances. However in this design the magnet was left loose and scrapes off anything captured as it wobbles around in its pocket, partly due to being in the high-flow location that was supposed to improve its performance.

Returned to circulation, iron particles lose their magnetic attraction as they are further 'mechanically worked' (crushed) and so the opportunity for sequestration is quickly lost. Many DIYers have noticed that placing a magnet in the used oil doesn't attract much.

This is why I encourage a very early oil change, to do the job the magnet is not doing.

Without refreshed oil, aside from bearing damage, particles continue to wear down through about 15,000 miles. Eventually they are no longer visible and can only be detected by lab tests. Many lab reports include a particle count for those over a certain size. A test done early on will have a high particle count and low iron PPM values, while later on the opposite is the case. The aluminium seems to be a side effect of this process, perhaps coming from the the surfaces the magnet is rubbing against.

* * * *
Reports of noise problems are showing up about twice a week in the small number of global forums I follow, mostly on 2019 vehicles but I think that's only because they are more likely to have higher miles. There doesn't seem to be any 'safe' miles where once you get past that the problem won't occur. We have two cases currently in NZ that are out of warranty, but much to my relief it's been reported by both owners that our importer is starting the repair process on a goodwill basis.

View attachment 21551
Hi-res image is at this link.
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Sorry, I should have said, "no unusual color for used oil." It was blackish brown, and definitely not a clear, light brown like the new oil I put back in.

Thanks for the additional detail and thoughts on the metallic particles, that makes sense that the larger particle count would diminish over time and the iron count would go up as those larger particles are ground into smaller and smaller particles.

Knock on wood, I have not noticed any wheel of fortune noise from the gear box, nor have I heard any rattling from the loose magnet inside. I've seen the posts here about placing magnets on the outside of the gear box to try and keep the internal magnet stationary, but at this point, I think that I will just keep up with more frequent GRO changes and hope that my transmission is done shedding any metal particles!

Thanks again for creating this thread, I have found it to be very helpful and informative, and I am happy to be a point on the curve now!
 
cmyoung72 said:
I finally did the GRO change on 9/16/23 and took a sample to send off to Blackstone Labs. We bought our Kona new in August 2019 and this is the first time that I've changed the gear oil. We've had no symptoms at all (~28,000 miles), knock on wood. Refilled with just shy of 1 quart of Redline MT-LV 70W/75W GL-4 and replaced the OEM drain and fill bolts with the Votex M18 x 1.5MM Magnetic Drain Plug (DP007) and new crush washers. Found the entire process to be very simple once I had the parts, and a syringe filler.

Did not notice any unusual color, sheen, or particulate matter in the old oil, nor did it have any noticeable smell other than what I would describe as "oil". Color was dark and oil felt viscus to the touch.

Blackstone Labs emailed results today and I wanted to add another data point to the running tally. I also wanted to get this group's thoughts on the results. See anything that should give me any concern? I'm thinking I will do a second oil change in another 10,000 miles and send that sample off for another test to compare with this first one.
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Should the fill plug be magnetic too? I thought replacing the drain plug with a magnetic one would be sufficient to capture any metal shavings?
 
An owner-added magnetic plug or two would in-theory help if installed from brand new. But they still have to 'compete' with the factory magnet so (one) might catch half the wear particles shed from gear meshing during break-in. Adding (two) magnet plugs means each might catch 1/3 for a total of 2/3. It doesn't matter what port you place them in, the GRU interior is a wild and crazy place while driving. I'm using two primarily because the Votex magnetic plug needs a much lower tightening torque than the stock plug and I only want to set the torque wrench once.

The 1/2 or 1/3 that are caught by the factory magnet will be worn down due to the fluttering motion and released in a non-magnetic state, and that is why I believe we see particles in the oil up to around the 5,000+ km mark. Had the magnet been secured, they would have stayed firmly planted for the life of the car.

But as the shedding of fresh wear particles drops off, all those older are fully crushed and essentially disappear into the oil and that's why it looks relatively free of visible particles later on. At that point adding a magnetic plug won't hurt, but won't help much either.

Short of opening up the GRU when new and removing their stupid magnet, the best plan is to carry out early oil changes to manually remove wear particles. 500, 1500 km at minimum, then optionally at perhaps once a year.

A new incident reported here today in NZ, confirmed GRU noise, owner hoping for an out of warranty goodwill repair.
upload_2023-11-9_12-34-40.webp
 
* * * *
"Reports of noise problems are showing up about twice a week in the small number of global forums I follow, mostly on 2019 vehicles but I think that's only because they are more likely to have higher miles. There doesn't seem to be any 'safe' miles where once you get past that the problem won't occur."


After discovering these Kona GRU owner threads as my 2019 Kona Electric's 35,000-mile service schedule indicated to "Inspect" this oil, and thereby getting informed about the issues and possible ameliorating actions, I've just had the GRU oil replaced on my Kona with 36,000 miles (~ 57,800 km) at my local Hyundai dealer's with -- at my request -- the Redline MT-LV 70-75 weight gear oil and the Toyota magnetic plugs {p/n 00341-18057) with Toyota crush washers (p/n 12157-10010), which I provided them with.

As far as I understand the "wheel of fortune" or bicycle-card-flapping noise, I haven't had that ...yet.

But even though the drain and fill procedure seems straightforward enough with ramps and a $10 gear-oil manual pump & tube set, jacking the rear to be sure to get all the old oil out would make it more complicated (and I would have to borrow or buy some jack stands to feel safe doing that). So I decided to see if my local dealer's service manager would authorize it with my chosen oil and plugs, and he agreed, after I made my case with the oil and plugs in hand, bolstered by the Hyundai TSB, a print of KiwiME's summary of the problem (dated July 2022), and a printout of the photo showing the Toyota magnetic plug vs the Hyundai OEM non-magnetic plug.

I spent $52 USD at an O'Reilly Auto Parts store for 2 quarts of the Redline oil (still cheaper than the Hyundai 70wt gear oil at $65 for 2 qts) and $17.75 * 2 = $35.50 for the Toyota magnetic plugs and $2.40 * 2 = $4.80 for the Toyota crush washers. Adding the 1 hour's labor at the dealer, costing $206, brought the total to $298 USD (prices include 8% local taxes) for the oil change.

I asked for a good quantity of the used oil, and gave the service manager a glass jar with lid to put it in. It's black, as usual. I've just requested the Blackstone Labs free kit for analyzing transmission oil, and can post the results when I get them.

For each of the next 20,000 mile intervals I'll do it myself. I like this car, and wonder of wonders, in the US, Hyundai sold the 2019 Electrics with an unlimited time/unlimited mileage warranty on the drive-train and battery to the first owner. So I want to keep it as long as I can. I bought the 2019 Kona after comparing it with my 2017 Chevy Bolt, and sold the Bolt (after its traction battery was eventually replaced). I've been lucky enough to own 2 electric cars, each of which had their LGChem traction batteries replaced under warranty.

Thanks for all the work and wisdom on this forum, and on this thread in particular!
 
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DavidR said:
wonder of wonders, in the US, Hyundai sold the 2019 Electrics with an unlimited time/unlimited mileage warranty on the drive-train and battery to the first owner. So I want to keep it as long as I can.
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Wise thinking. The actual range is way above the EPA listed for many and generally is quite mechanically reliable as well.
If that same warranty had been offered in Canada, I too would see little reason to upgrade. ;)
I am sure when your Lab results are posted, @KiwiME will be happy to add them to his graph.
 
DavidR said:
... But even though the drain and fill procedure seems straightforward enough with ramps and a $10 gear-oil manual pump & tube set, jacking the rear to be sure to get all the old oil out would make it more complicated (and I would have to borrow or buy some jack stands to feel safe doing that).
...
For each of the next 20,000 mile intervals I'll do it myself.
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With the car on ramps, all the oil comes out, that's not a problem. To install the new oil I use a funnel attached to a length of clean tubing from above pushed fully into the fill opening. It's far less messy than a pump and allows the certainty of a precisely-measured amount to be installed, 1.00 litre.

I back the car off the ramps so that it's level and pour the measured amount into the funnel. It won't hurt driving the car a few metres without oil.
If you leave the car on the ramps it won't accept that amount because all the fluid volume is forward of the fill opening. I don't concern myself as to whether or not the fluid drips out to confirm the final level. However, a rag placed under the filler opening is advisable to catch any that does, otherwise it drains into the rear underside cover.

After filing I re-install the filler plug from above (an essential step) just finger tight, then drive it back up the ramps to torque the two plugs and finish the job.
 
Thanks for the details of your routine -- I'd seen your funnel-and-hose setup but wouldn't have thought of backing off the ramps with the gear reduction unit _empty_ to get the car level to fill it!
Question: While the car is still up on the ramps, and after torquing on the bottom drain plug with new crush washer, perhaps putting in 1/4 of of the 1.1 quarts/1.0 litre wouldn't be amiss if I then put the top fill plug on finger-tight before backing the car down the ramps? None of that small amount would be lost to overflow from the fill port, would it? (Though I guess I'd need a bit of a stepladder to get some of the oil in from above.)

That would make me feel better about backing it down -- by having the drain plug torqued on and ~some~ oil in the GRU.
I know it's not the same kind of parallel, but I once ruined a perfectly good 180,000-mile Corolla engine by rushing the finish of an oil change and forgetting to tighten and check the spin-on filter -- heading off to work, it only took 3 miles before the idiot light came on and I got over my disbelief to get the clutch pushed in and the ignition turned off. But the knocking had started.

Hmmm -- maybe that experience was another reason I wanted to move to an electric car -- I'm not missing all those unneeded hundreds of moving parts requiring periodic maintenance!
 
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Oil-wet gears can run under load without damage for short times (~30 seconds) and rolling-element-bearings much longer (15 minutes) without being refreshed with oil.

Engines have hydrodynamic journal bearings that cannot tolerate much more than about 10 seconds of a disruption to the oil supply. Starting a cold engine is almost comically risky considering that's how it's designed to work in every ICE car. The one reason to always pre-fill the oil filter during an oil change.

You could add half the oil or more while on the ramps and it's not hard to reach. But ignoring this is really not a problem either.

Unrelated to all of this, you may get a loud 'clunk' when entering D due to the parking pawl withdrawing after acquiring a load when sitting on the ramp. Gave me a fright the first time I heard it.
 
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