In some of the latest cars out there, you can change gears simply by pressing a button, turning a knob or toggling a small Variable Speed Drive Motor joystick. Yet at the same time, plenty of different automobiles still require motorists to make use of one foot for the clutch pedal and another for the gas, all while using one hand to manipulate the gear-change lever through a distinct design of positions. And several other current cars don’t possess 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 transmitting (CVT), each unit must do the same job: help transmit the engine’s output to the traveling wheels. It’s a complex task that we’ll try to make a bit simpler today, starting with the fundamentals about why a transmitting 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 begin 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 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 lower gear means optimum functionality with the wheels moving slower compared to the engine, while with a higher gear, optimum performance includes the wheels moving faster.
With a manual transmission, gear shifting is handled by the driver with a 
gear selector. A lot of today’s vehicles have five or six forwards gears, but you’ll find older models with from three to six forward gears offered.
A clutch can be used to transmit torque from a car’s engine to its manual tranny. 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 sized gears deliver much less torque and allow the car travel quicker.