Algodoo

dafuq
this is not a transmission. That's more like a clutch and all in all i'd say it hasn't got any complexity on it.
Also use more density on your scenes and try to stick to realistic sizes (this car is 20 meters long, you can make a box of about 5x2 and use it to make your next car shape). also use high density on everything if you do that, like 400 or 500 density. And never use friction or restitution on engines and gearboxes