Gear Noise Reduction

Try using a little Red N Tacky on the gears.  It make my F3's 2343AA run quieter.  Only need a light film.  Worked for me.  

No all nation experience, just general thoughts.

  If you encase it, a soft material like styrene should dampen sound better than metal.

Usually a thicker grease like R&T is the key, but it can have the reverse effect. If so, clean and move to a heavy gear oil.

Thrust washers can help sometimes too by eliminating some run out (wobble).

A lot of the noise may be caused by the gears used in the tower.  The original gears were cut straight spur gears and are just flat out noisy.  Lubrication may help a little but because they're straight cut spur gears there's really not much you can do.  The intermediate version, referred to as constant mesh, was quieter but more expensive to make (the gears are cut at an angle).  The last version used delrin chain and sprockets.  They are probably the quietest of the three but, because A-N weakened the sprocket hubs by removing material, so they would fit on their drive components, the sprockets usually crack.  Once they crack the sprockets have to be replaced   When I replace the sprockets I modify the drive components so I don't have to remove the delrin hub material.  I've had a few still crack over time but not many.