LEGO MOC 3-speed gearbox with comfortable manual step switch by Don_Santos | Rebrickable - Build with LEGO
Amazon.com: LEGO Technic COMPLETE GEARBOX ASSEMBLY 2 x 4 x 3 1/3 Trans-Clear Wormbox gear motor REDUCER block Mindstorms robotics ev3 NXT transparent robot building power functions part 6588
Building instructions for 10 speed sequential gearbox used for RWD applications
Lego Technic Sequential Gearbox Instructions | The Lego Car Blog
Someone Made a Working Six-Speed Gearbox Out of Legos
Super Easy Building Instructions - 3 Speed Gearbox - 7 studs - Lego Technic | Lego gears, Lego, Lego technic
LEGO MOC Lego Technic lockable automatic two speed gearbox [with free instructions] by SJ_LegoFan | Rebrickable - Build with LEGO