In a few of the most recent cars available, you can shift gears simply by pressing a button, turning a knob or toggling a little joystick. Yet simultaneously, plenty of different vehicles 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 definite pattern of positions. And several other current cars don’t have any traditional gears at all in their transmissions.
But whether or not a vehicle includes a fancy automatic, an old-school manual or a modern-day consistently variable transmission (CVT), each unit has to do the same work: help transmit the engine’s output to the traveling wheels. It’s a complicated task that we’ll 
try to make a little 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 blend ignites in the cylinders, the pistons start moving up and down, and that movement is 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 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 overall performance with the tires moving slower than the engine, while with an Variable Speed Transmission increased 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 have five or six forwards gears, but you’ll find older models with anywhere from three to six ahead gears offered.
A clutch is utilized to transmit torque from a car’s engine to its manual transmitting. The various gears in a manual tranny allow the car to visit at different speeds. Bigger gears offer plenty of torque but lower speeds, while smaller sized gears deliver much less torque and invite the car travel more quickly.