Never really built a gearbox before but knew the basics of a 2 and 4 speed boxes so i smashed them together and build this kinda small 8 speed gearbox : r/legotechnic
Someone Made a Working Six-Speed Gearbox Out of Legos
Lego Technic video about Lego 2 Speed Automatic gearbox - worm gear prototype. Includes build instructions.
LEGO MOC 2 Speed Gearbox by thatbrickguy | Rebrickable - Build with LEGO
MOC] 2 speed gearbox : r/legotechnic
2 speed lego gearbox
Quick Build – 2-Speed Gearbox with Reverse! - LEGO® Technic™ Videos - LEGO.com for kids
6 Speed Gearbox MOC Brick Set – Toy Brick Lighting