Get a hex wrench, a small screwdriver, a toy tire lug wrench, quick-connecting terminals and an electric radio controlled motor.
Take out the cover of the car then remove all necessary parts that block the access to the motor then remove the cover of the gear box.
Detach the screws holding the motor in place and store them in a safe place. Remove the motor from the car.
Detach the motor from the power leads and the pinion gear using the hex wrench. Make sure the hex screw stays on the pinion gear.
Attach the new motor to the old pinion gear utilizing the hex wrench.
Find the negative and positive markings on the new motor. Attach the red lead to the positive end and the black lead to the negative end on the motor side and on the car side.
Put the new motor with the attached pinion into the motor slot. Use the screws previously detached to hold it in place or use the supplied screws by the new motor.
Attach the cover on the motor and then reattach the removed parts and toy car casing.