Been there.....Done that.........while at John's, I had the chance to play with his filterflo, at first was a little worried about shifting speeds while running.....but guess what?...you can!.....the speed won't change from fast to slow while running, but the switch can be flipped back and forth with NO issues.....actually the fingers that are held by the solenoid, retract while the machine is running at high speed.....so no damage could occur while running......
probably the most damage that may occur is when trying to shift speeds, the operator will shut the machine off, flip the switch, and turn back on, not allowing enough time for the clutch to slow down to a stop before restarting the machine.....