In a few of the most recent cars available, 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 distinct pattern of positions. And several other current vehicles don’t possess any traditional gears at all in their transmissions.
But whether or not a vehicle includes a fancy automatic, an old-college manual or a modern-day continually variable tranny (CVT), each unit has to do the same job: help transmit the engine’s output to the generating wheels. It’s a complex task that we’ll try to make a bit simpler today, you start with the fundamentals about why a tranny is needed to begin with.
Let’s actually begin with the typical internal combustion engine. As the fuel-air mix ignites in the cylinders, the pistons start moving up and down, and that movement can be 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 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 lower gear means optimum functionality with the tires moving slower compared to the engine, while with a higher 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 forward gears, but you’ll discover 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 transmitting. The many gears in a manual tranny allow the car to visit at different speeds. Larger gears offer lots of torque but lower Variable Speed Drive Motor speeds, while smaller sized gears deliver much less torque and invite the car travel more quickly.