In a few of the newest cars in the marketplace, you can change gears by simply pressing a button, turning a knob or toggling a little joystick. Yet at the same time, plenty of different vehicles 
still require motorists to make use of one foot for the clutch pedal and another for the gas, all while using one hand to control the gear-change lever through a definite 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 has a fancy automatic, an old-school Variable Speed Drive Motor manual or a modern-day continuously variable tranny (CVT), each unit has to do the same work: help transmit the engine’s output to the generating wheels. It’s a complicated task that we’ll make an effort to make a bit simpler today, starting with the basics about why a transmitting is needed to begin with.
Let’s actually start with the typical internal combustion engine. As the fuel-air mixture ignites in the cylinders, the pistons start upgrading and down, and that motion can be 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 quicker 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 lesser gear means optimum performance with the tires moving slower compared to the engine, while with a higher gear, optimum performance includes the wheels moving quicker.
With a manual transmission, gear shifting is handled by the driver with a gear selector. Many of today’s cars possess five or six forward gears, but you’ll find older models with from three to six ahead gears offered.
A clutch can be used to transmit torque from a car’s engine to its manual transmitting. The various gears in a manual transmitting allow the car to visit 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.