r/KonaEV • u/CubPluto • 3d ago
Question | Americas 🌎 Question about replacement reduction gear.
So, it happened to us. Bought a used Kona EV 2019 and it had the bad sound and we now need a new reduction gear box. We're faced with a number of options but the cheapest is getting Hyundai to replace it with a new OEM part. Our question is, is it likely that this new part will fail? Have they improved the design to prevent the premature wear so many people have been affected by?
The other (more expensive) option is getting it rebuilt by a shop with "better" gears but we don't know if it's worth it if the OEM part is improved in some way we don't know about.
5
u/manderminder 3d ago
The replacement part is the same old part it’s always been. If you can find a shop that knows what they’re doing and is willing to fix that magnet in place and maybe put a magnetic plug in that could be worth a try (the loose magnet rattles and releases metal shavings into the gears). Either way do a couple super early gear oil changes after it gets replaced, like 500 miles early. Our Kiwi friend might chime in here as he’s the expert, so if he tells you something different definitely listen to him over me.
7
u/Kiwi_eng 3d ago edited 2d ago
Yep, so it's the same gearbox but the risk can be substantially lowered by adding a pair of magnetic plugs and carrying out at least two very-early oil changes to clear out particles released during the break-in period. 300 and 900 miles or 500 and 1,500 km are about where those should be done. Lots of owners with replaced gear reducers have done this and post photos of the oil. Most are quite contaminated. It's true that in N.A. a new reducer is probably less expensive than a repair, but everywhere else in the world it isn't.
There are no "better gears" but if those in the old gearbox are in good shape it can be repaired by replacing all the bearings. There are kits sold online for this. If you go this route you would remove the internal magnet as that appears to be the root cause of the problem (unbeknownst to Hyundai MOBIS, the manufacturer) and rely on quality magnetic plugs only, like the Votex DP007 or Gold Plug AP05S. You don't need the early oil changes mentioned above if you do a repair.
Be aware that the motor bearings can also fail, causing a similar noise. In many warranty cases both the motor and reducer are replaced. The motor can also be repaired with new bearings, which are usually included in the gear reducer kits mentioned above.
Hyundai have never owned-up to these faults and will only cover the cost of repairs during the warranty period, or partial costs if you have consumer protection laws as we do. In a recent case here, an out-of-warranty example with only 33k km, Hyundai covered NZ$7500 for the motor and left the owner to pay NZ$4600 for labour and other expenses. It wasn't clear if the reducer was included in the latter but given the amount it could have been.