Any automatic car is not just a manual car without a clutch pedal. The systems and mechanisms that are responsible for automatic gear shifting in the transmission work differently compared to a manual transmission. Let us learn in detail about the different types of automatic gearboxes in India and how to take care of them.
A torque converter-based automatic transmission is the most reliable and serviceable of the lot. A torque converter is nothing more than a hydraulic fluid-filled turbine drum assembly that, as the name suggests, converts and multiplies the torque generated by the engine. It also serves the purpose of a clutch found in the manual transmission. that is, it isolates the connection between the engine flywheel and the drivetrain during braking. Since a torque converter is the oldest form of automatic gearbox, it is the simplest construction and therefore easy to maintain. It should be noted that torque converters are prone to higher torque loss compared to other automatic gearboxes. This requires that the gearbox be carefully driven uphill. Most torque converters feature manual override only for the purpose of uphill driving. A torque converter gearbox does not require any different driving style to maintain gearbox life, apart from changes in driving habits when changing from manual to automatic.
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Unlike other automatic transmission systems that have limited gear ratios through which the system shifts for optimum speed and torque, the CVT unit comes with drive pulleys and a belt for power transmission. This system provides the user with unlimited gear ratios while driving and ensures that optimum torque is available at all times. It should be noted that CVTs fail at high torque inputs and thus cannot be seen on vehicles with larger engines. Since a CVT system doesn’t have actual gears like other transmissions, CVT gearbox oil is different from others. While the purpose of other transmission fluids is to stay on the surface of the gears to keep them lubricated, the transmission fluid in a CVT collects metal debris on the pulley surface to prevent belt slippage. Since CVTs don’t have actual gears, a car with a CVT transmission lacks towing capacity and therefore shouldn’t be used to haul heavy loads.
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As its name suggests, a dual-clutch transmission is made up of two clutches with alternating gear trains attached to each clutch, thus while one clutch handles the engagement of odd gear ratios, viz. 1St.3dr5the gears, the other clutch engages even gear ratios. Although the presence of two clutches makes the DCT the fastest shifting gearbox even compared to the manual transmission, it also increases the complexity of the gearbox. This complexity of the mechanism results in higher manufacturing cost, repair cost and also a high failure rate. This requires users to modify their driving style a bit compared to the transmissions mentioned above in order to take care of their DCTs. A DCT works by switching between the two clutches that are coupled to their respective gear ratios. Therefore, when a car with DCT is sitting in traffic for more than a minute, it is advisable to put your car in neutral to prevent clutch wear and transmission maintenance. Care should also be taken not to shift the car into park when stopping for short intervals, as constantly shifting between parking and driving will lead to increased clutch wear.
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An AMT is the result of technological advancement in the conventional manual gearbox. The work of a clutch pedal and gear lever is done by electro-hydraulic components controlled by a dedicated controller. This shows that the AMT has some features like manual transmission in combination with certain limitations of hydraulics and electronics. Unlike all of the automatic transmissions mentioned above, the AMT does not have a dedicated parking gear on its shifter. Someone switching to AMT from any other automatic transmission should make sure they have set the parking brake after shifting the car into neutral when parking the vehicle. An AMT unit has considerable torque loss and therefore needs to downshift and keep the engine speed in the power band when going uphill. Similarly, you also have to be careful not to put the car in neutral when going downhill, as it renders the engine braking almost useless.
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