As 3D printers evolve, so will the quality and usefulness of their creations. Right now, basic home setups like the $400-ish Kossel mini are capable of churning out pieces that you can use to build your very own working scale model gearbox (and engine).
The video below shows the operation of a replica box that goes together with a 22R engine which Toyota used in its cars until the late 1990s on models like the Celica, Cressida, 4Runner and Hilux. It shows gears being shifted and how it affects the speed (and rotation direction) of the output shaft.
It’s pretty cool to take the time to do something like this, but other than impressing the proportion of friends that are as nerdy as you are, there’s really not much use for it…
Check out the videos after the virtual jump; the second one is of the engine.