I drive a Twizy 80 Technic from 2013 with 11.000 km on the clock. When I drive around 50km/h constantly, you hear a high frequent grinding noise. It stops when you slow down or accelerate.
The Renault dealer (also ZE certified) already replaced the differential, because they saw that was in bad condition.
But what is this grinding noise coming from? I’ll contact my Renault dealer soon, but wanted to ask some more experienced owners first ;).