As compli-cated as It all may seem at first, the operational aspects
of a 2-speed transmission are actually quite simple to understand. Power from the engine or motor starts the whole drive process. First gear engages as a result of the
connection between the clutch and the clutch bell on the engine itself. As the engine's RPMs and (the car's top speed increase), the 2-speed's clutch shoes or arm will kick out and "grab" the bell housing via centrifugal force. That's when second gear kicks in. First gear is actually still being driven by the engine, but it's not turning the RPMs to keep up with the RPMs of second gear. That's why there is also a one-way bearing housed inside the larger first gear or 2-speed bell housing. When second gear has engaged, the RPMs become so high that the gear shaft support-
ing the gears actually free-spins inside the one-way bearing, thus disengaging first gear.
Hope that helps