Transmissions
The transmission of your car, truck, or SUV is the part that determines the gear of the engine. If you grew up with a manual transmission, then you have experienced managing the gear using the clutch pedal and the gear shifter. It is necessary to make sure the engine is using the right gear for its speed.
Nowadays, most cars use an automatic transmission. These have internal instruments that track the speed of the car and the revolutions per minute of the engine, among other things