What Does D3 Mean In A Car

Driving a car can be a lot of fun when you get the hang of it. Manual transmission can be quite challenging for some until they master the stick and know what to do with it. Most of it is taken care of in an automatic transmission, and a driver need not concern themselves with the way the gears work. 

If you are driving an automatic transmission and have experience driving a manual transmission, you would be well aware of the difference in driving both. You must also be familiar with the manual transmission option available in automatic vehicles. 

What Does D3 Mean In A Car?

A D3 is a gear option you can find in many automatic transmission cars. D stands for the drive, and the number 3 stands for the gear, so D3 stands for driving in gear 3.

When you put the car in D3, the engine locks in gear 3 and does not shift to any other driving gear on its own. 

How To Use The D3

Not all automatic cars have a D3 option in them. Many manufacturers are scrapping out this gear option from their automatic transmission cars. This does not mean using this gear is not recommended. Using the D3 option in your automatic car can be beneficial if you know when to use it and which roads to use it. 

If you are still not very sure about the D3 gear in your car, here are some ways in which you can use it:

  1. You need to put the car in “D,” the drive mode, and only start the engine to start an automatic car. This is the lowest gear option for the car.
  2. Once you start the car in “D,” it will start moving slowly and use the maximum torque until it moves more smoothly.
  3. Now you can rev up your engine to increase the speed, provided the road conditions are good enough. When you hit around 30 or 40 km/h, you can shift the car to “D3”. Remember to push the button to change the gear. The button is there for a reason – to prevent the car from changing gears by a wrong nudge or mistake.
  4. When you are on D3, your car can cruise at medium speed and reduce the torque, thus saving more fuel. Since the car is locked in D3, it won’t keep shifting to the lowest gear and coming up, which can strain your engine and consume more fuel.
  5. If the road is not smooth or if you need to slow down the car, remember to bring the gear to “d” and only slow down the engine. It is very similar to driving manual transmission cars. When you are in a higher gear, you need to slow down before shifting to a lower gear, or else the engine will stall.
  6. Once you gain speed again, you can shift back to D3 if you want to.

When To Use The D3?

Automatic transmission vehicles are designed and meant to shift gears on their own. You do not have to change the gears as you would do in a manual transmission. So, when the D3 is provided in an automatic car, when exactly do you use it? Do you use it, or just let the automatic car do its own thing?

The D3 was specifically provided in automatic cars for a reason – safety. When you drive downhill, the car can gain momentum and move to a higher gear without you having to press down on the accelerator. When the engine is at the fifth or the highest gear, the torque is less, and it will take time for the car to stop when you hit the break.

So, when you lock the car in D3 as you go down the hill, the engine is engaged and can achieve engine braking. It also reduces the airflow that aids in a high manifold vacuum, thus causing your car to lose speed.

You can use the D3 mode when you are driving up the hill as well. When driving up a slope, the automatic transmission will mostly be stuck in a low gear to provide more torque and power to the engine. 

If the road is smooth and empty, you are bound to pick speed, and the automatic transmission will move to higher gears, resulting in lesser traction. When you lock the engine in D3, sufficient traction makes the journey safer.

Why Use The D3?

When there are other gears in the car, why use the D3? Why not just let the engine be on the automatic transmission? Why should you even take control over something designed to be automatic?

Here are a few advantages the D3 has to offer:

1. Reduces Maintenance Costs

When you are going downhill and engaging the D3, your engine will be braking and preventing the car from sliding down at high speed and requiring you to step on the brake.

When you step on the brake and speed up again, the gears go down to the lowest and need to move up. The torque is more, making more RPM and consuming more fuel. 

Using the D3, the engine is already braking on its own, and you won’t have to step down hard on the brake. As a result, your brake pads and shoes can last longer. Overall, you can cut back on maintenance costs that can go up if you drive up or down the hill often.

2. Safety

As mentioned earlier, the engine will be braking and prevent the vehicle from speeding down the hill. Even while driving on slippery roads during rain, the car will be more controlled and easier to brake.

While driving too fast at a higher gear, the traction is lesser, causing the wheel to spin too fast to be stopped suddenly if there is a requirement. This is why you see cars spinning out of control when they have to brake suddenly while speeding.


Cars are designed to keep you safe when you drive from one point to another. Manufacturers have many provisions to ensure safety, regardless of the terrain or the distance.

D3 was introduced in automatic transmission cars for added safety. Though many automatic cars do not have this feature anymore, many of them have the option to change to complete manual transmission.

Liam Dare

As CEO of ReplicarClub.com, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.