The sound came from the location of the gear / auto-clutch. When I carefully examined it, it seems like there was also a leaking of gear oil al over the swing arm / drive belt casing.
It only appears/heard when I turn the wheel at certain speed. My goodness, back to the mechanic I supposed. But I was not free at the moment. I will have to wait for the next weekend to bring it to the mechanics.
I wonder how much will it cost this time..................
