Manual vs Automatic Transmission

Manual vs Automatic Transmission

Mark Sanyal MORE

When it comes to transferring power from the engine to the wheels, the battle comes down to Manual vs Automatic transmission. Automatic Transmissions have for years been out of reach for most consumers, but with cars like the Tata Nano and Maruti Suzuki Celerio coming with Automatic Gearboxes, these systems are now within reach of the masses. We’ve gone ahead and compared both the Manual and Automatic transmissions to help you decide on which system will suit your driving needs.

Manual vs Automatic Transmission

Mechanics

Manual transmission systems are much simpler when compared to their Automatic counterparts. In Manual transmissions, the power is transferred through a gearbox where, using the clutch, different sets of gears are locked and unlocked to allow higher speeds through the different gear ratios while still functioning within the narrow operating limits of the engine. The Automatic transmission, on the other hand, uses a planetary gearset to produce different gear ratios by using a single set of gears. Similar functionality but very different ways to get the job done.

Manual transmissions drive power from an engine to a layshaft which is directly connected to the gears. The gears themselves are connected to the driveshaft and ride on bearings, so that when power is transmitted through a selected gear, only that gear spins the driveshaft, while the others freewheel without interfering. The gears are selected by a gear known as the collar, which can only be moved between gears when the clutch is engaged. Once the collar engages a gear, the driveshaft transmits the power of that gear ratio to the wheels.

If you found the operation of a Manual transmission complicated, prepare yourself, because the Automatic transmission is a completely different level of complexity. There are three main components that operate to change those gears automatically so that you don’t have to make the effort. These are the torque converter, planetary gearset and the clutch bands.

The engine’s power is transmitted through the torque converter which uses a phenomenon known as fluid coupling to create torque. This torque then passes through the clutch bands which decides which gear to select. This is the part that replaces your gear changing efforts and automates the entire process. Once the clutch bands decide what gear to drive in, the planetary gearset comes into play.

All pieces of an Automatic transmission exposed

 

The planetary gearset consists of a sun gear, planet gears, and a ring gear. The sun gear is connected to the planet gears, which revolve around the sun gear. The planet gears form a link between the central sun gear and the peripheral ring gear. The planet gears are kept in set positions by what is known as the planet carrier. It is the interplay of these three gears that produces a variety of gear ratios by simply making one gear the input, another gear as the output, and the remaining gear is held fixed.

You might be wondering why you just went through the technical (and most probably confusing) explanation of how Manual and Automatic transmissions work. After all knowing how the respective transmissions work has brought you no closer to being in any position to form an opinion as to which might be best for you. Well, by understanding the complexity of both transmissions, you are now in a better position to understand the inherent consequences of these complexities.

Complexity to Ease

For all the complexities of the automatic transmission, the end result is that it translates to one of the most comfortable driving experiences you can have. That’s not to say that Manuals aren’t comfortable, but the numerous gear changes that you go through, especially in bumper-to-bumper traffic, sometimes makes Manual transmissions a chore to drive. When the Automatic transmission system carries out all the shifting, there is less effort on the driver’s part, which will surely reduce the stresses of driving on Indian roads. For just ease of use, Automatic transmissions take an easy win in any driver’s book. But for every positive in the world, there have to be negatives. For Automatic transmissions, that negative comes in the form of reduced control.

Traffic Spinny

Automatics make driving through these situations less stressful

The Sacrifice of Control

The reason most drivers prefer Manuals over Automatics is the degree of control you get over the car’s speed and power. The extra work of operating the clutch is worth it when it translates to precise control of how the power is applied. This makes it easier to drive in hilly areas, for example, as choosing the appropriate gear for the uphill or downhill gradient is required to drive efficiently and safely in those situations. Automatics, on the other hand, suffer in such situations where a higher degree of control is required. These transmissions constantly switch from the lower to higher gears and back again as the terrain keeps varying. This shortcoming can be reduced to some degree by using the manual mode present in most Automatic cars but even then, the transmission goes through a lot of stress and wear because of the higher workload it has to perform.

Costs

Automatic cars are, invariably, more expensive than their Manual counterparts. This is easier to understand owing to the more complex nature of the Automatic transmission and the higher number of components involved in its construction. This complexity makes Automatic models of cars more expensive than the Manual variants of the same cars. The Honda City SV AT costs a lakh more than the City SV Manual. This is true across all manufacturers who offer Automatic variants for their models.

This complexity also translates to higher maintenance costs as the high number of components in addition to the intricate construction of Automatic gearboxes increases the maintenance costs of Automatic cars. Let’s take the transmission fluid as an example. When it comes to change transmission fluids in Manual transmissions, it is a simple matter of locating the drain bolt, draining the fluid, and filling the fresh fluid. Automatic transmissions require a fluid flush to remove the fluid present in the torque converter before filling fresh fluid into the transmission. The fluid flush requires a separate machine to properly remove the old fluid from the transmission system.


 

The choice of transmission when buying a new cars is quite straightforward. Most buyers choose Manuals because of the familiarity with the transmission system while those choosing Automatics are looking for the ease of use and don’t mind paying the extra cost. With the launch of the new GenX Nano AT, Automatics have become more accessible to general consumers. Automatics are also attractive propositions in the used car market with most automatic cars that are prohibitively out of reach when new, becoming very affordable when used. In the end, it comes down to whether you want more control or more comfort.

 

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