In a few of the newest cars on the market, you can change gears by simply pressing a button, turning a knob or toggling a little joystick. Yet Variable Speed Transmission simultaneously, plenty of different automobiles still require motorists to make use of one foot for the clutch pedal and another for the gas, all when using one hand to control the gear-shift lever through a distinct design of positions. And many other current cars don’t possess any traditional gears at all in their transmissions.
But regardless of whether a vehicle has a fancy automatic, an old-college manual or a modern-day constantly variable transmitting (CVT), each unit must do the same job: help transmit the engine’s result to the driving wheels. It’s a complicated task that we’ll try to make a little simpler today, starting with the basics about why a transmission is needed in the first place.
Let’s actually begin with the normal internal combustion engine. As the fuel-air combination ignites 
in the cylinders, the pistons start upgrading 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 in the cylinders and the whole 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 wheels moving slower than 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 via a gear selector. Many of today’s cars have got five or six ahead gears, but you’ll find older models with anywhere from three to six forwards gears offered.
A clutch can be used to transmit torque from a car’s engine to its manual tranny. The many gears in a manual transmission allow the car to travel at different speeds. Bigger gears offer plenty of torque but lower speeds, while smaller gears deliver much less torque and invite the car travel quicker.