Need general drive train expertise

Originally Posted by Mike Marandola

I have heard that you are unable to shift on the fly because of that. Is that true?

Edit: Never mind. The Sonic Shifter video I posted higher in this thread shows that shifting on the fly with a servo is possible.

Not quite. That video shows a free spinning output. Once the transmission is put under the load of a moving robot it will require a bit more force to shift, making servo shifting no longer shift on the fly.