The 7 Types of Transmission Explained
Not so long ago, the only choice that car buyers had with regards to vehicle transmission system was between manual and automatic. This was the case until the 90s, when electronics started becoming an integral part of vehicles in general, transmission systems included. Now, it appears that every new vehicle comes with a new type of gearbox that you’ve never heard of.
CARMUDI wants to help you make sense of the technical jargon and abbreviations that relate to gearboxes. Whether you’re looking at a new or used vehicle, below are the seven types of transmission you’ll see today.
The manual transmission is the oldest type of transmission still in use, and its simplicity practically guarantees its relevance forever. Manuals–whether four-, five-, or six-speed–use a system of interlocking flywheels that connect the engine’s rotational energy to the system’s input shaft. From there, fixed gears are then engaged by the syncro and gear-selector fork. A clutch works to disengage the engine from the transmission so gear shifting can occur. The driver controls this clutch via the clutch pedal. The driver may then choose the appropriate flywheel for the desired speed using the stick shift connected to which the gear-selector fork is connected to. When the driver releases the clutch pedal, the flywheel and pressure plate come together, enabling the engine to turn the transmission flywheels.
The automatic transmission, introduced in 1939, does all of the above with minimal driver intervention. In fact, it does most of its functions automatically, as the name suggests. Automatic transmissions make use of a torque converter to transmit the engine’s power to the transmission, using hydraulic fluid to make the connection and effectively eliminating the need for a clutch pedal to serve such functions.
A manual-automatic (aka semi-automatic, manumatic), is primarily an automatic transmission equipped with a regular clutch and gear setup. However, the actual gear shifting is done by sensors, processors, actuators, and pneumatics instead of a clutch pedal/stick shift combo.
Continuously Variable Transmission (CVT)
This type of gearbox replaces the steel gear wheels of typical of automatic transmissions with a belt-and-pulley system for changing gears. The absence of fixed gears allows a CVT to accomplish a wide range of ratios, transfer power to the wheels uninterrupted, and permit the engine to spin at maximum speed.
Dual Clutch Transmission (DCT)
DCT used two separate shafts for changing gears—one manages odd-numbered gears, while the other handles even-numbered ones. Each shaft has its own clutch. The system’s biggest advantage is that it can shift to a higher or lower gear in a fraction of a second, allowing for seamless acceleration. However, DCTs have been known to have problems with noise, lurching and stalling, hesitation, and lack of throttle response, among others. As such, vehicles with DCT are often in need of constant monitoring and maintenance.
Direct Shift Gearbox (DSG)
DSG is just like DCT, but without the fuss. It does away with DCT’s problems by simply disengaging one clutch instead of allowing it to turn when not in use, as is the case with DCT.
This automatic transmission type is designed to behave like a manual gearbox, and it does so by providing the driver with a shifter (either paddle or floor). However, as it is basically an automatic transmission, it uses a torque converter instead of a clutch pedal. That said, its unique attribute is that it allows the driver to override the automatic mode and switch to manual mode when road conditions call for it, such as an uphill climb or a steep downward slope.