[Simon Strauss]

I'm a bit confused as to how the pins are being forced down away from the gears when they are not engaged. I assume that the whole system is modeled after the tumbler of a key and lock, but what is to prevent the springs from getting caught or damaged while a gear is not engaged, if the spring is in the gear and rotating around the shaft with it. It may not be an issue but i think you may want to consider A)shorter springs and a second pin attached to it that stays in the gear, like that of a lock with your pins that are already there taking the place of what would be the teeth on the key. This might prevent gears from getting jammed. Also B) I'm assuming that you are curving the top of the pins so that they are flush with the outside of the tube that they are in and because of this I'm worried that the round pins you have in it now might rotate and cause themselves to no longer be flush. Because of this i think that square pins might be more advantageous in that they will only go in directions you want them to.

-Simon

P.S Ive never built a shifting transmission so these issues maybe completely irrelevant or nonexistent, you and others here know much more about this than i do.