In a few of the newest cars available, you can change gears by simply pressing a button, turning a knob or toggling a small joystick. Yet simultaneously, plenty of different vehicles still require drivers to use one foot for the clutch pedal and another for the gas, all when using one hand to manipulate the gear-shift lever through a distinct pattern of positions. And several other current vehicles don’t have any traditional gears at all within their transmissions.
But whether or not a vehicle includes a fancy automatic, an old-college manual or a modern-day constantly variable transmitting (CVT), each unit has to do the same job: help transmit the engine’s result to the traveling wheels. It’s a complicated task that we’ll make an effort to make a little simpler today, starting with the fundamentals about why a transmitting is needed to begin with.
Let’s actually begin with the typical internal combustion engine. As the fuel-air blend ignites in the cylinders, the pistons start moving up and down, and that motion is used to spin the car’s crankshaft. When the driver presses on the gas pedal, there’s more fuel to burn in the cylinders and the complete process moves faster and faster.
What the Variable Speed Transmission transmission does is change the ratio between how fast the engine is spinning and how fast the driving wheels are moving. A lesser gear means optimum efficiency with the tires moving slower compared to the engine, while with an increased gear, optimum performance comes with the wheels moving faster.
With a manual transmission, gear shifting is handled by the driver via a gear selector. A lot of today’s vehicles have five or six ahead gears, but you’ll find 
older models with from three to six forwards gears offered.
A clutch is used to transmit torque from a car’s engine to its manual tranny. The various gears in a manual tranny allow the car to visit at different speeds. Bigger gears offer lots of torque but lower speeds, while smaller gears deliver much less torque and allow the car travel more quickly.