Transmission or a gearbox performs the basic function of channelling the power generated by the engine to drive the wheels. Now to do this there are different types of gearboxes available and while the mechanical process of gear shifting are the same the procedures to change them varies in different types of transmission. With a small exception of a continuously variable transmission (CVT), a gearbox is usually finished in a metal case that contains series of gear levers; hence it derived the name gearbox. Each gear has a specific gear ratio to differentiate the spinning of wheels to that of the engine. The force that causes the rotation inside the engine popularly known as torque enters the transmission through the engine shaft and passes through the gears before coming out through output shaft. The final process on the torque reaching the wheels depends on whether the engine is place at the front, mid or at the rear end and also if it is front-wheeled, rear-wheeled or all-wheel drive. Manual, automatic and CVT are the popular and common types of the gearbox available on the cars these days. But which one should you buy specially in Indian traffic? Does your car’s mileage actually vary depending on the transmission? We try to address these questions below.
Stick-shift or manual gearbox is the most commonly used transmission type globally. Most of the current driving population globally would have at least learnt driving on a manual gearbox before evolving to automatic gear shifts. On the old classic cars like the Fiat Padmini Premier or even the Ambassador have seen the gear shifter just below the steering column, but any modern car the gear stick is placed vertically on the center console of the car and is connected to the transmission via a linkage. The clutch plays a crucial role between the engine and the transmission to supply the required power the wheels. A vehicle with a manual gearbox is always a more fun to drive and more interactive. However, given the traffic scenario in the country the manual gearbox can frustrate and irritate you. It is also said that once you can drive a car with a manual gearbox makes it easier to drive a car with any gearbox. Three-speed manual gearbox were common in cars in 1940s, more gears were added to the cars as the technology improved and cars started to evolve. Cars with four-speed gearbox ran on the roads for decades, then five and now six-speed gearbox are getting common. Premium cars like the Chevrolet Corvette, Porsche 911 does offer seven-speed manual gearbox.
Once considered as a luxury on cars, a transmission that shifts itself has now become a widespread commodity and going forward the buyers would prefer and automatic over a manual for ease of driving. There are two different types of automatic gearboxes on cars. The conventional automatic is connected to the engine via a hydraulic torque converter that helps to shift the gear lever without the driver’s intervention and the second on is the dual-switch gearbox (DSG) which is a two-in one transmission where twin electronically controlled shafts manage gear selection. Most of the Volkswagen group cars like the Volkswagen Polo, Volkswagen Vento, Skoda Octavia, Skoda Superb, Audi Q7 etc comes with this DSG gearbox. The process of gear change is done hydraulically or electronically by monitoring important parameters such as speed, throttle position and the engine’s rotation speed. In the case of an AMT gear box (Automatic-manual transmission) there is an electronically monitored sensor that upshifts of downshifts the gears based on engine’s rpm. Most of the cars with AMT the gears can also be changed manually using the shift levers on the gear stick. The automatic cars have two-pedals that make it impossible to stall the car the engine given its configuration.
The myth that an automatic car is less fuel efficient than the manual is not true. Modern electronic technology have made it possible for an automatic car to give almost the same mileage as a manual driven car. In many cases the automatic cars tend to perform better on the mileage front as there is no human intervention on the gearbox. Globally, four-speed automatic transmission served the cars for the longest time. Today, six-,seven- and eight-speed automatics are common. ZF has introduced 9-speed gearbox for many premium cars. More gears helps in more acceleration and improved fuel efficiency.
The other type is the continuously variable transmission or popularly known as the CVT gearbox. While many first time CVT users find this gearbox very slow on shifting it is also considered as the smoother than the traditional automatic gearbox. The CVT relies on a pulley and belt system that allows it to provide infinite numbers of ratios. It is also found in automatic scooters, ATVs and snowmobiles. CVT also helps in improving a car’s fuel mileage making it a prime reason for hybrid vehicle manufacturers to put a CVT on a hybrid car. To improve the acceleration, CVT are often mated with paddle shifters that help in quick gear shift. Most of the Honda cars in India are equipped with a CVT gearbox, Maruti Suzuki Baleno hatchback also gets a CVT gearbox.
Which is the right transmission for you?
The kind of vehicle you want and your driving style are two factors you should consider before you buy your next car. If driving dynamics are not on top of your car’s must have list and you need a car that will make you less tired in traffic then go with a CVT or automatic gearbox is something you should consider. However, if you are a first time driver, learning to drive or an auto enthusiast who is looking for more driver-car interaction then a car with manual transmission should do the job. Globally, the trend to own a car with automatic transmission is on the rise. In India, most of the automatic variants even on affordable cars are sold only on the top variants. Fuel efficiency on modern cars is almost the same on a manual or an automatic car. So either have it peace in traffic or get a manual for a fun and engaging driving time.