also would be worthwhile asking to which level in the bevelbox the oil is filled. some fill via the breather all the way up, others only via the filling hole and not higher. difference is 0,4l i guess. does it make a difference in noise level?
If indeed the side hole is called the "fill hole", then that kind of answers the question as to how high the level is meant to be.
I can't think of any reason to go to all the trouble to engineer and machine a large hole on the side if it's meant to be filled to the top via the vent hole.
