[dgbint]

The electric motor is inside the platform.
This is most likely to be OK.

The gearbox is on the outside of the platform.
Yes, it does have oil inside.
It may be low, but that is unlikely.

There is an elastomer between the motor output shaft and the gearbox input.
This is to reduce backlash.
This can wear.
If worn. yes it can make a bit of a grinding noise.
If you can locate the part, it should be quite cheap.

There's a bit of labor to pull it all apart, and put it back together again.

If one side is worn, the other is likely to be close behind, so replace both.

Good luck