2021 Hyundai Kona EV, buzzing sound upon acceleration

I have a 2021 Kona EV with 50,000 miles (bought it late Dec 2020). At somewhere between 37K-40K miles I began to notice a subtle buzzing sound that seemed to be coming from dashboard area when acceleration. My wife couldn't hear it from front passenger seat.
When I brought it in for "routine service"...(tire rotation), I told them about this buzzing. When they checked it out, it turned out that the reduction gearing was going out, had to be replaced. It's been in the shop almost 3 weeks so far, as they're waiting on parts. I've read others saying that when they heard this buzzing, the dealer replaced the fluid and the buzzing stopped. This may be a temporary fix. It's likely that if it's making noise, the problem may be deeper than just the fluid. I'm thinking that I'm lucky my service coordinator and service technician were thorough and conscientious. Some dealers may be taking a shortcut and trying to save time and money by just changing/adding fluid.