My Ebike had almost 6000 miles on it and from last week it started to make crazy noises and vibrations from the hub motor. And the bike was not riding as smooth as before. It feels like loosing power or something is dragging it from behind. So, I opened up the hub motor and found out that one of the planetary gears bearing was messed up. So I have replaced it with a new one. Now it is very smooth and no crazy noises, just the normal motor noise.
You can see in the beginning of the video (before replacing the planetary gear) the hub motor was making grinding noises and the wheel was slowing down and stops real fast.
At the end of the video (after replacing the planetary gear) you can see that the hub motor is running smooth with normal motor noise and the wheel was keep on spinning for a long time.