In some of the newest cars in the marketplace, you can change gears by simply pressing a button, turning a knob or toggling a small joystick. Yet simultaneously, plenty of different automobiles still require motorists to use one foot for the clutch pedal and another for the gas, all when using one hand to control the gear-shift lever through a definite design of positions. And many other current vehicles don’t possess any traditional gears at all within 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 job: help transmit the engine’s output to the traveling wheels. It’s a complex task that we’ll try to make a bit simpler today, you start with the fundamentals about why a transmission is needed in the first place.
Let’s actually start with the typical internal combustion engine. As the fuel-air blend ignites in the cylinders, the pistons begin upgrading and down, and that motion is utilized 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 whole process moves 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 efficiency with the wheels moving slower than the engine, while with an increased gear, optimum performance includes the wheels moving quicker.
With a manual transmission, gear Variable Speed Transmission shifting is handled by the driver with a gear selector. A lot of today’s vehicles have five or six ahead gears, but you’ll find older models with anywhere from three to six forward 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 travel at different speeds. Larger gears offer plenty of torque but lower speeds, while smaller sized gears deliver much less torque and allow the car travel more quickly.