When is the O/D function used on automatic transmission vehicles?
Today's automatic transmission cars have advanced, electronically controlled gearboxes and often come with a semi-automatic mode, so the O/D function may appear on the automatic transmission lever.
What is Overdrive (O/D)?
O/D stands for OverDrive, this mode is the highest level in automatic transmission. When using O/D, the vehicle will improve performance when traveling at high speed.
Most new car models today are equipped by the manufacturer with O/D mode in the gearbox to give users a complete experience when using. This mode is also automatic if the driver sets it in advance or presses the "Eco Mode" button.
As for older automatic transmission cars, the O/D mode will be activated manually by the owner with a button or lever. When OverDrive is activated, the car engine will operate at very low rpm, ensuring the engine creates less noise during operation at a certain speed and saves fuel more effectively.
O/D is the highest level in automatic transmission. (Illustration photo).
When the O/D lamp is not illuminated, the ON display indicates that this mode is active. The user's vehicle can operate in the highest gear and save fuel at low rpm.
Conversely, when the O/D light is on and displays OFF, the vehicle will not allow the user to use one or more high gears to ensure traction. At this time, the vehicle is in normal driving mode, the highest gear cannot be selected.
How to use O/D on automatic transmission vehicles
Nowadays, some cars still have an O/D button. When the O/D is ON (the light is not on), it means that the button is locked and your car will not select the highest gear. You are now in normal driving mode.
Simply put, the default O/D function is OFF (indicator light is on), allowing the use of all gears in the gearbox (to save fuel). When turned ON, the vehicle will not allow the use of 1 or more high gears to ensure traction. For example, when O/D is turned off, the vehicle can only use gears 1-4, and gears 5-6 are considered non-existent.
When going downhill
The braking system is used a lot when you are driving downhill or stuck in traffic. Driving downhill requires you to put a lot of pressure on the brake pedal continuously.
If you use O/D in those situations, it will keep the RPM above idle without straining the brakes and engine.
When accelerating
According to the driving experience of many drivers using automatic cars, when you drive over 100 km on new cars (80 km on old cars), the RPM increases and the car engine starts to use more pulling power. At that time, when O/D is active, it will help the engine reduce pressure and reduce RPM.
However, you should not use O/D when you are driving below 80 km or while driving in the city as the speed tends to be uneven there. O/D prolongs the life of your vehicle's engine and transmission only if you use it wisely.
