The Gear System In Automatic Cars


It is increasingly becoming difficult to find a manual car on the Ugandan market save for large trucks.

Naturally, cars with automatic transmissions are less complex to drive when compared to their manual counterparts, which perhaps could explain why they have become more popular in Uganda.

Surprisingly though, in Europe, auto transmission cars are less popular with many drivers preferring manual transmission cars.

In Uganda, most cars are from Japan where automatic transmitters are quite popular. This might explain why automatic transmitters are more popular here considering that market of origin prides in them.

Most cars have the usual setup of P R N D 2 and L. These are initials you will find in auto transmission car, which of course might vary in different car formats.

However, today we shall stick to the usual starting with P which is an acronym for parking.

The P acronym is pretty self-explanatory. Simply it is used when the car is parked. It basically restricts the car from moving in either direction.

A parking pawl (thick metal pin) prevents the transmission from rotating but the car’s non-driven road wheels will continue to rotate freely.

For this reason, it is recommended to use the hand brake (or parking brake) because this actually locks (in most cases) the rear wheels and prevents them from moving.

Furthermore a car should be allowed to come to a complete stop before setting the transmission into parking to prevent damage.

Usually, P is one of the only two selections in which the engine can be started with the other being Neutral (N). In many modern cars and trucks, the driver must have the foot brake applied before the transmission can be taken out of parking.

Moving on is R that stands between P and N. It basically stands for reverse. In others wards, it gives the car the ability to move backwards.

Before R is engaged the car must come to a complete stop. Many modern automatic transmission cars have a safety mechanism, which to some extent prevents (but does not completely avoid) the driver from accidentally engaging the car in reverse when in a forward movement.

Neutral which is abbreviated as N is the buffer that disengages transmission from the wheels.

So the vehicle is able to move freely under its own weight. It is one of the selections where the engine can be started.

D is the drive selection that powers the car forward. It is the only selection where gears can freely be changed.

Then comes the less commonly used selection of Two (2), which stands for second, and L that stands for low.

Two (2) basically limits the transmission to the first two gears or locks the transmission in the second gear in some models. This can be used to drive in adverse conditions such as slippery and muddy roads while L basically locks the transmission in the first gear.

Whereas Two (2) is useful in muddy conditions, you must always be careful when you choose to use it.

Since the engine is restricted to only one gear (first), the tyres might slip under increased rotation.

Nonetheless it’s quite efficient if you have heavy loads and driving uphill.

On most cars the automatic transmission has three speeds and overdrive as the fourth.

Overdrive as the fourth gear

Overdrive allows the engine to have less rpm with higher speed in order to have better fuel efficiency.

When you switch it on, you allow the transmission to shift into overdrive mode after a certain speed has been reached.

When it is off, you effectively limit transmission to the third gear. In normal driving conditions the overdrive should always be switched on.

You may need to switch it off when driving in hilly areas or when there is need to downshift the gear for sudden acceleration and increased power at high speeds.

However, with newer cars, you might find different configurations with some having options for manual shifting, among others but at least they will have most if not all of the above.