How To Compare Automatic vs Manual Transmission Parts

Americans take the fact that most cars sold in North America have an automatic transmission. For the rest of the world, though—particularly in Europe and Asia—manual transmission automobiles are preferred. This is perhaps due to cheaper maintenance, cheaper initial cost, and a general sense of control over one’s vehicle. Some subcultures even believe that real men only drive stick.

True enough, you get more control over a manual vehicle, and the fact that you have a mechanical clutch rather than a hydraulic one would ensure more efficient transfer of power, and therefore better fuel efficiency. Driving a standard transmission vehicle also allows for more spirited driving, because of the level of control.

Automatic and manual transmission vehicles are not really worlds apart. Most cars of similar make and model usually have exactly the same engines under the hood, the same trim levels and interiors, and looks. What sets these apart are the actual gearbox and the gear selection levers.

Both manual and automatic gearboxes contain the gears, which connect the engine with the transaxle (or the axle, as in the case of rear-wheel drive vehicles) and ultimately with the wheels. However, the similarities mostly end there, as the technologies for shifting gears differ.

Manual transmission vehicles use a clutch to disengage the engine from the wheels when at a neutral or stopped position. When the clutch pedal is fully depressed, the clutch pads disconnect, and the engine is essentially disconnected from the transaxle and the wheels. When the clutch pedal is partially lifted, the clutch pads turn each other due to friction—called “slipping”—and power is partially transferred from the engine to the wheels, bringing the car forward (or backward) gradually from a stopping position.

Once the clutch pedal is completely lifted, the clutch pads fully engage, and there is full transfer of power from the engine to the wheels. The same process repeats as a driver upshifts as the vehicle speeds up, but while running, “slipping” is no longer required, as one can directly select gears and engage the wheels, assuming that the speed matches the gear selected.

On an automatic transmission, the torque converter takes the place of the clutch, and gears are arranged in a planetary gear arrangement. Rather than using a clutch to manually disengage the engine from the wheel, an automatic transmission car relies on the transfer of transmission fluid at high pressures from within the torque converter, in order to transfer power from the engine to the wheels using turbines at both ends.

When the car is stopped, the main the turbines from the engine side of the torque converter still turn, but the transmission fluid is diverted back. When a car is starting from a standstill, the main turbine drives fluid into the other side, until the automobile starts running. Both turbines are usually locked together at speeds of about 40 to 50 miles per hour, to ensure efficient energy transfer.

In terms of vehicle interiors, a manual transmission vehicle would usually have the stick shift at the center console beside the driver. This would be manipulated in an H-pattern, and most modern cars have six positions, ranging from 1st to 5th and the reverse gear. On an automatic vehicle, on the other hand, the gear selector would include Park, Reverse, Neutral, Drive, and Low gears. The gear selector can be located at the center console, or at the steering column. Some modern automatic transmissions also have a “tiptronic” or semi-automatic system, which mimics the control that a full standard transmission can offer, but without the need to manually clutch.

One of the advantages of standard transmission over automatic is easier maintenance. An automatic gearbox is usually heavier than a manual one, and because of the use of a torque converter rather than a clutch, more frequent maintenance is required. An owner needs to make sure he has adequate transmission fluid at all times, for the torque converter to work properly.

Arguably, the best advantage an automatic transmission has over manual is the driving ease and convenience it offers, especially in long haul driving and stop-and-go-traffic. Automatics also lessen the likelihood of human error, such as downshifting at high engine revolutions. The classic question of automatic vs. manual is best answered by the driver’s preference. If you prefer ease of maintenance and added level of control, then manual is the best choice. If you need comfort above all else, then automatic transmission is for you.


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