In some of the newest cars available, you can shift gears simply by pressing a button, turning a knob or toggling a little 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 when using one hand to control the gear-shift lever through a distinct design of positions. And many other current vehicles don’t possess any traditional gears at all in their transmissions.
But regardless of whether a vehicle includes a 
fancy automatic, an old-college manual or a Variable Speed Transmission modern-day constantly variable tranny (CVT), each unit has to do the same work: help transmit the engine’s result to the generating wheels. It’s a complex task that we’ll try to make a bit simpler today, starting with the basics about why a transmission is needed to begin with.
Let’s actually start with the typical internal combustion engine. As the fuel-air combination ignites in the cylinders, the pistons start 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 off 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 lesser gear means optimum overall performance with the wheels moving slower than 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. A lot of today’s vehicles have five or six ahead gears, but you’ll find older models with from three to six forward gears offered.
A clutch is used to transmit torque from a car’s engine to its manual transmission. The various gears in a manual tranny allow the car to visit at different speeds. Larger gears offer lots of torque but lower speeds, while smaller gears deliver less torque and invite the car travel more quickly.