By VIGNESWARAN CHANDRAN

For those who are unsure what a transmission system does, it is pretty much the system that connects the engine to the wheels to propel the vehicle forward and backwards in accordance to the chosen gear, as well as determining the speed of the vehicle based on the gear that you engage. This system is fairly complicated, and with the advances in modern technology, the system is now almost completely computerized to ensure that you get the best fuel consumption with the gears that you engage in.

Choosing the car with the right transmission is pretty much a dilemma that most car buyers would face before they purchase the car of their choice. The choices are pretty much limited to automatic and manual vehicles, and what used to be a manual-transmission domination world is now completely the opposite, as the automatic-versions have taken over from their manual counterparts and have started to dominate the market. Auto-cars are easier to drive, and does not pose a burden on the driver to move the gear level or control the exchange of gears through the use of the clutch as everything is done automatically.

On the negative side, the auto-vehicles are slightly more expensive than their manual-counterparts, and consume more fuel as well. And automatic transmission systems are also slightly more expensive to maintain, and more prone to maintenance issues and breakdowns (and they would prove to be more expensive to replace as well).

Manual transmission vehicles might be slightly more difficult to drive (especially when the traffic is heavy), but the initial investment for these cars are considerably lower, and they are also cheaper to maintain. Manual cars also consume less fuel than their auto counterparts, and are less prone to breakdowns. The manual versions are also more fun to drive, as you can manually control the engine, thus racers and those who enjoy aggressive driving prefer manuals compared to auto. You have complete control of the vehicle with a manual transmission, contrary to the automatic transmission where the ECU controls the speeds that you travel at as well as the fuel consumption of the vehicle.

Just like that of a manual transmission, the automatic transmission's primary job is to allow the engine to operate in its narrow range of speeds while providing a wide range of output speeds.

Without a transmission, cars would be limited to one gear ratio, and that ratio would have to be selected to allow the car to travel at the desired top speed. If you wanted a top speed of 80 mph, then the gear ratio would be similar to third gear in most manual transmission cars.

You've probably never tried driving a manual transmission car using only third gear. If you did, you'd quickly find out that you had almost no acceleration when starting out, and at high speeds, the engine would be screaming along near the red-line. A car like this would wear out very quickly and would be nearly undriveable.

So the transmission uses gears to make more effective use of the engine's torque, and to keep the engine operating at an appropriate speed. When towing or hauling heavy objects, your vehicle's transmission can get hot enough to burn up the transmission fluid. In order to protect the transmission from serious damage, drivers who tow should buy vehicles equipped with transmission coolers.

­­The key difference between a manual and an automatic transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission, the same set of gears produces all of the different gear ratios. The planetary gearset is the device that makes this possible in an automatic transmission.

Let's take a look at how the planetary gearset works.