An automatic transmission is a type of a vehicle transmission that automatically changes gear ratios as you drive your vehicle and accelerate. There are many advantages of automatic transmission as it frees the driver from having to shift gears manually.

The automatic transmission comes with several gear modes, which allow the driver to select the appropriate mode as required by the driving condition. The different gear modes are described below.

Different Automatic Gear Modes

P (Park). This mode locks the movement of the vehicle in any direction. P is the only mode in which cars can be started, other than N (Neutral). The P mode is used when you have to stop and park the car for long time. i.e at your house, office, shopping center parking, etc. In most cars, you

won't be able to pull out the car key from the ignition, unless you put the car in the P mode. A car should come to a complete stop before setting this transmission mode., to prevent damage to the gearbox. In many cars, the foot brake must be applied before taking the gear out of the P mode.

N (Neutral): It is same as P (Park) mode, except that the movement of the vehicle is not restricted. You should use this mode if you are driving in a stop-and-go situation when you do not want to take the extra effort of continuously applying foot brakes when the car should not be moving. This mode can also be used if the car has to be towed. In N mode you can switch the car engine on and off.

R (Reverse): This mode allows the vehicle to be driven backwards. To select reverse, the driver must depress the gear level, press the foot brake or the shift lick button (varies n different vehicles).

D (Drive): In the D mode, you engage the gear, allowing the vehicle to move forward through its range of available gears. How many gear ratios are in the gearbox i.e 4, 5 or 6 or more, vary in different car models.

3 (Third): This mode is not available in all models.  When selected, the transmission is limited to the first three gears only. This mode is also recommended when driving downhill.

2 (Second): This mode limits to first 2 gears of the transmission only. It is useful when you want more acceleration, or driving on snow or ice, as well as when going downhill or climbing uphill with heavy load in the car.

1 or L (First or Low): Both 1 and L are used in different cars. This mode puts the car in 1st gear and locks in it. This mode is used if you're going uphill with very heavy load in the car. You can also use this if you are going downhill and wants to increase the braking effect.

Other Non-Common Gear Modes

The following modes are rare, and found in very specific model of vehicles:

S (Sport): The Sports mode operate same as the 'D' mode. The only different in driving the car in this mode is that the gear shifts up much faster, maximizing all the engine power, during acceleration. In this mode, the vehicle also down shifts the gear much faster compared to the D mode, giving the maximum effects of engine braking.

B (Brake): When this mode is selected, the car applies engine braking, used when going steep downhill. This also reduces the driver's needs to apply hard foot brake. This mode doesn't down-shift the gear but uses engine power to reduce pulling, required while driving downhill.

M, -/+ : This option allows the user to manually shift down or up the gear anytime during the driving, by overriding the current automatic gear selection. This mode may be useful when going uphill in a fully loaded car, and the and you suddenly feel need to down-shift the gear to suddenly accelerate the car more. The + option allows you to shift the gear up and _ sign allows you to shift the gear down.

W (Winter): In a very few car models, W mode has been provided. When engaged, the car's second gear is selected instead of the first gear, when start moving. This mode is used when driving on snow or ice, to reduce likelihood of wheel spinning on ice or snow.

D2 to D5: These modes uses only the first two, first three, first four and first five gears only.

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Tags: Auto Transmission Vehicles, Automatic Gear Modes