If you compare the width of the two, you will notice that the noisey gears are slight wider due to the fact that the quiet gears are slightly more narrow in order to accommodate the run quiet plates.
However, I do not know if the material used is the same. Perhaps one has more nickel than the other? Perhaps a better annealing process was used? This I do not know.
Big Mike, can you check with Marlin on this as to what he thinks and get back to us?
