Automatic Robotic 4 speed Gearbox

Hi! I created an adaptor for mijael08 gearbox (link below) to make it automatic ( robotic automated gearbox) and I installed it in a RC car with bluetooth controls.. It has 4 gears + reverse + neutral, steering and I programmed it to act like a real car, it revs faster and goes slower to idle and steering is adaptable and is slowly steering to the centre, like a real car.
The gearbox does not need to be printed with all the parts, only the gears, shafts and mounting plates are enough for our setup. It uses 6 bolts to mount the adaptor on to the gearbox ( 2 holes need to be drilled ).
It uses 3 MG995 servomotors with levers to change gears. The mechanism uses 3 levers to change between gears, 1 lever for gear 1-2, a longer lever for gear 3-4 and a lever for reverse gear. The levers are driven by 3 MG995 servomotors. I recommend to use minimum 30% infill on the gears or more border layers because of the wear. When shifting gears, the gearbox grinds a little bit until