Help on shifting gear linearly precisely

[woodstock]

Hi All,

I am a beginner and am trying to figure a compact way to shift my driving gears along one direction in a gearbox. Should I use a set of worm gears or linear actuator? Do I need a stepper or limiter to ensure the gear move to the exact position to mesh with the follower gears? Attach is the example. 

[Aventador2004]

The actuator is probably the best choice, worm gears have too much slack.

[woodstock]

thanks. I am working on a version with the new (orange) rotary selector, too. but it will be restricted to 4 positions per rotary selector. 

[Rudivdk]

You could also have a look at this topic, it has a lot of gearbox examples which might give you some inspiration: