![Lego Compact 3 Speed Automatic Gearbox Instructions - Lego Technic Mastery - YouTube | Lego mindstorms, Lego technic sets, Lego technic Lego Compact 3 Speed Automatic Gearbox Instructions - Lego Technic Mastery - YouTube | Lego mindstorms, Lego technic sets, Lego technic](https://i.pinimg.com/564x/8f/fe/8c/8ffe8c05d51b153b74f92adb8e7572af.jpg)
Lego Compact 3 Speed Automatic Gearbox Instructions - Lego Technic Mastery - YouTube | Lego mindstorms, Lego technic sets, Lego technic
![my first (working) automatic gearbox! By any chance, is it uncommon to use pull back motors for this? it seems like an obvious choice, but i always see people using non-lego springs : my first (working) automatic gearbox! By any chance, is it uncommon to use pull back motors for this? it seems like an obvious choice, but i always see people using non-lego springs :](https://i.redd.it/k7ohyv6oo5f71.jpg)
my first (working) automatic gearbox! By any chance, is it uncommon to use pull back motors for this? it seems like an obvious choice, but i always see people using non-lego springs :
![Sliding worm 3-speed automatic gearbox - LEGO Technic, Mindstorms, Model Team and Scale Modeling - Eurobricks Forums Sliding worm 3-speed automatic gearbox - LEGO Technic, Mindstorms, Model Team and Scale Modeling - Eurobricks Forums](http://www.brickshelf.com/gallery/Nazgarot/Gearboxes/3_speed_automatic_crawl_gearbox_with_spring_and_rubberband.png)