In some of the latest cars out there, you can shift gears by simply pressing a button, turning a knob or toggling a small joystick. Yet at the same time, plenty of different automobiles still require motorists 
to use one foot for the clutch pedal and another for the gas, all while using one hand to control the gear-shift lever through a distinct design of positions. And many other current cars don’t have any traditional gears at all in their transmissions.
But whether or not a vehicle includes a fancy automatic, an old-school manual or a modern-day continuously variable transmission (CVT), each unit must do the same work: help transmit the engine’s result to the traveling wheels. It’s a complicated task that we’ll try to make a bit simpler today, starting with the fundamentals about why a tranny is needed in the first place.
Let’s actually begin with the normal internal combustion engine. As the fuel-air blend ignites in the cylinders, the pistons begin upgrading 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 off in the cylinders and the complete process moves Variable Speed Transmission faster and faster.
What the transmission does is change the ratio between how fast the engine is spinning and how fast the driving wheels are moving. A lower gear means optimum performance 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. Many of today’s cars have five or six ahead gears, but you’ll find older models with anywhere from three to six forward gears offered.
A clutch is utilized to transmit torque from a car’s engine to its manual transmitting. The many gears in a manual tranny allow the car to visit at different speeds. Bigger gears offer plenty of torque but lower speeds, while smaller sized gears deliver less torque and allow the car travel quicker.