Welcome to the site Josse, as Simon suggests it's worth checking the chain tension to make sure it's not pulling really tight on the front sprocket bearing.
If it is internal gearbox bearings, then the whine comes from loosing the correct gap between corresponding gears as the bearings allow the shafts to move closer together or further apart. If that's the case you are better off not using it as this will trash the gears, you may be able to replace only the bearings otherwise.
Oh, i'll second Triggers advice also.