Buzzing noise

Thanks. Crossing my fingers for you that it lasts! I'm still confused as to which parts are which. Sometimes, as in your case, the reduction gear is referred to as a seperate part but others it seems as though the "drive unit" is an assembly of motor and reduction gear/drive train. And then there are those who had their "motor" swapped out. I can't ascertain whether there's a difference in which parts are being changed or whether it's just people using imprecise language. All I know is I hope my garage is swapping "everything" that could be making my godawful noises!

 

these were the replacement parts:

44500-18EA1 Gear Drive Unit Assembly (aka Trans Gear Drive)
00232-19091 Electric Vehicle Battery Syst (I was told THIS was the Oil they had to add)

 

This clarifies things a bit (for me). The motor unit is separate from the gear unit. I still wonder which one my dealer intends to replace? The gear unit is the light coloured one. Motor unit is darker

 

I had to search your posts to find out what your dealer said:

So that's the two big lumps in the image. Good thing because replacing just one is not likely to be a permanent fix.

This appears to be the coolant needed as a top-up for either a battery or motor change.

 

That's my worry. They SAID they were replacing everything but I really don't know if that's actually what they're doing or if the order form for parts had all the correct boxes ticked! And I've seen so many stories from people having one or the other replaced, some with good results but others right back in the soup having to get something else replaced later.

 

I still don't understand WHY this defect is happening on a nearly new car. Gives me pause about reliability of this vehicle since I only have 8,500 miles on it. If that component dies again, after 4 years (??), I imagine it would be very expensive to replace again. (I sold my '85 BMW with 250K miles on it!)

 

A question for the many engineering experts and aficionados here: Is it reasonable to expect that a car, such as mine, afflicted with the "noise", whatever the cause, would have an observable or measurable loss of efficiency resulting in range loss?

 

Plenty of new cars have problems because designing and manufacturing a perfect product is very, very difficult. But my suspicion is that the wheel of fortune noise and dirty oil both slipped by the design and development review process, a bit surprising given that the Kona/Niro are the results of several years experience with the Kia Soul and (classic) Ioniq EVs. Not helping the situation is that the new G-EMP platform is totally different and as-such Hyundai/Kia will have little interest in pursuing solutions for these issues.

If the mechanical powertrain had sufficient added friction to create a noticeable loss of efficiency you'd soon have a failure. "Lost" energy in the form of heat would show itself quickly in the form of melted metal and catastrophic bearing or gear failure. Only making unusual noises doesn't require much energy.