Algodoo

It's a thyme gearbox that changes variables according to custom variable, set by oncollision events. (The purple box labeled gearbox control).

It's meant to be used in games and on simple cars, not focusing on mechanical functionality, but simple simulation of gearboxes, set any values you want, you can adjust via oncollide the torque and speed of each shift.

on this scene:
Up arrow to accelerate, down arrow to brake.

(non-numpad numbers)
1- first gear
2- second gear
3- third gear
4- fourth gear
R- reverse

As an example i used my VW phaeton.

if used give credit please!