Fascinating video to watch – Thank you so much for taking the time and trouble to make it.
...... I think you should increase your prices a little bit more - You certainly deserve it !

The 1st failure that happened on the original gear reducer was that the soft steel sealing plug normally pressed into the tail end of the input shaft had dropped out and allowed oil to travel through the hollow shaft to the splined coupling.  There is an O-ring on the motor shaft just inboard of the spline to keep grease (to lubricate the spline) out of the carbon brush, so once you pulled the GRU off the motor, the oil simply spilled out.  Clearly the loose plug also managed to break up and destroy the bearing, taking out the casting as well, but the several other reported cases had caught the failure before that happened. This defect seems to be independent of, and far less common than the next one.

The 2nd failure is due to a defect present in all H-K EVs from the 64kWh Soul up to the end of the 1st-gen Kona/Niro (2024 and 2023 MYs).  No doubt to cut production costs they changed the GRU internal magnet from a square shape to one that's round, clearly less expensive but isn't well-secured.  That doesn't sound like a problem at first and I expect the person who suggested this may have even received an award for their idea but in reality it was a dumb change.  A loose magnet will not retain steel wear particles because the magnet is constantly moving under the influence of oil flow.  Images taken of the magnet after moderate kms by myself and another owner show it to be clean rather than covered in particles as it should be. In your case and several others, if the magnet happens to become overwhelmed with particles due to a failure in progress it can choke-up and start to work correctly, which is what you saw.

The owner here clearly knew about some of this and had installed a pair of what look like "Gold Plug" brand magnetic plugs which are very good quality. But that only helps if done when the car is brand new and only reduces the risk somewhat.  Another mitigation that seems to be more effective is to carry out oil changes at 300 and 900 miles (at my suggestion) from new.  Ideally you would also disassemble the GRU and remove the loose magnet as well, but that's seems inconvenient to say the least.  Hyundai to this day seem to have not realised their mistake.  Most examples survive the onslaught of circulating particles during break-in (0-2,000 miles approx) but in all cases the bearings suffer damage that may eventually result in a noise.

Excellent work , looking forward to get your services.

It's not just the oil that needs changing, the gearbox bearings are also worn out, which is why they're not very good. You have to use a good brand to avoid these problems, as that's the main issue with Hyundai and Kia. That's what happened to my Soul ev after 100k kilometers...

Fantastic video....wow 22 plate 220,000 miles.  Would love to know the SoH of the battery and if the battery coolant has been changed every 40k.  That's the main issue with these cars moving out of warranty, however does it really need a complete flush?  Lot of unknowns which is why data from cars like this is invaluable.

Loving your videos 😊

Hello, thank you for this Video! GREAT stuff! Like your Cannel!

Bright yellow jacket - perfect for working on cars! 👍

good job, also, you managed to keep clean your jacket, well done 👍

I just changed the reduction gear oil in my '20 Kona with 40k miles and added the magnetic drain plugs. Also has dealer exchange the inverter coolant and new Continental tyres are on order. Should be good for a while. 🙏

Ovidiu, the lifetime of the passenger cars is set to 240,000km. This Kona did around 320,000km, before the first issues appeared. It outperformed quite well the intended lifetime. Without a doubt changing the oil can prolong the life of transmission, but it won’t run forever

Thanks a lot for filming, editing and sharing all these repairs !

Great work! It would cost no less than 5k in dealership 😢.

Der burde nok været monteret et bedre leje, selv i vindmøller har der problemer  i mellen gearet, men 220.000 uden at skifte olie, så er det ringe vedligeholdelse. tak for jeres gode videoer Henrik DK.

Any idea why on a kona ev 2023 water leaks inside the tailgate panel when you open the boot?

23:10 re-gas? Wasn’t it possible to not disconnect A/C?

Hello. I wanted to know the price to change the electrical connector reducer; I have this problem on mine.

220k Miles with neglect? TBH, I think this Hyundai car deserve an award.

I need to get this done on my 19 kona ev. How many hours did this job take? Do you need to pull any fuses for the high voltage battery? Or is it safe to unplug those orange plugs?

Lifetime oil: when it goes wrong, probably the entire GRU is finished, so it is the end of it's lifetime......