[quote=some young guy]
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Originally Posted by 11 pistons... I will try to break it down in a fairly subtle manner. 2 for wings, 2 for center lift, 2 for rear lift, 2 for shifting ;), 1 for ball grabber, 2 for elev release.[/QUOTE
i have some expiriance with "shifting" in the transmition. our robot from last year shifted gears with two 2 stroke pistons. there was just one problem, we had alot of truble shifting from high to low and from low to high. the pistons pushed the gears back and forth just enough to mesh with the high and low gear. the problem we had was the gears wouldn't mesh, they would just hit into each other and spinn. this made the loudest sound 'cause the teethe of the gears would be rubbing up against eachother making the high pitched sound. i just wanted to know how you guys were shifting and if you had that problem. if you did have that problem, how did u solve it. my team eventualy solved it. we bought a sec of micro files and started fileing away at the gaps inbetween the teeth to make them mesh easier (dave lavery told us to do that one) but it still never worked rite.
by the way...i wish my team can wire like that...its amazing, it make me want to cry 
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The more succesful pneumatic shifting trannys don't actually slide gears back and forth -- this is problematics for exactly the reason you just described. Look at the Technokat's 2003 tranny for an example of how to build a shift on the fly tranny (i'm sure there are others, but our bot was involved in an unhealthy (at least for our bot) relationship with the Technokat's bot, so I remember theirs the most). Instead ofmoving gears, they moved a dog which basically selected which gear (the one for high gear or the one for low gear) was locked to the driveshaft, allowing the gear that wasn't in use to slide on the driveshaft. They used a dog, three massive prongs on each side, slightly angled, that mated with three depressions on each gear. Neither gear was locked to the shaft, but the dog was, so by engaging the dog with the gear they wanted they locked that gear to the shaft allowing the other to just spin.
I'm not sure how clear that was, go look up pics from last year for a better idea.