What Is D3 In A Car: Understanding How Gears Work In Automatics

by Conner Mckay

As most automakers are letting go of the age-old manual transmissions in their vehicle, you have to know the many kinds of gears from which you can choose when it comes to an automatic transmission. Apart from the obvious ones such as the R (Reverse), P (Park), D (Drive), and N (Neutral), other things are written on the indicator of the lever of an automatic transmission, including L, S, and D3. This may make you wonder: what is D3 in a car? The D3 you find in an automatic transmission stands for Drive 3 – a gear that engages and locks the 3rd gear so the vehicle will not shift on its own to other gears. 

There are plenty of benefits of using D3 that highly depend on the road condition the vehicle is being driven on. If your car’s automatic transmission comes with a D3 gear, then keep on reading. We have also listed the few advantages of this gear, some frequently asked questions as well as a bunch of general information to help you understand this new gear better. 

What Is L In A Car?

You don’t have to be a car enthusiast to know that the L in an automatic transmission stands for low. In this mode, the engine stays in the lowest gear ratio possible – the first gear.

A few older automatics stay at 1st gear whereas, for a lot of modern ones, it transitions to the next gear at a specific range of RPM (revolutions per minute) to prevent damage and reduce strain on the transmission and engine of the vehicle.

Where To Use?

The gear L can be used in uphill or downhill climbs that require steady and low speed – driving on congested, moving traffic. For instance, if you are driving uphill an unfamiliar twisted road (also see this video on how to do that safely).

What Is 2 In A Car?

Similar to the L model, a transmission’s 2 mode means the engine will use only the first two gears of the vehicle. This will maximize the RPM of every gear to create the required pull from the engine. In other models, however, it will begin and lock in second and move up only when a specific range of RPM is crossed to prevent engine damage.

Where To Use?

Since the RPM is maximum during this phase, the 2 driving modes are needed when driving up quite a steep road so you can fully use the vehicle’s torque. You can also move to this mode when driving downhill to employ engine braking – removing any additional stress from the brakes of your car. 

Although, we suggest you take notes that this can affect the fuel efficiency of the vehicle as you will be using more gas at higher RPMs. That being said, safety should always be your number one priority.

What Does D3 Mean In A Car?

It may be completely plausible that you have never engaged the D3 gear in your vehicle while driving. Some people are expert enough to not have to ask, “What is D3 in a car?” as they have already got some good use out of this mode

D3 is the gear that lets you engage the first 3 gears of your car (gear 1 to 3) while driving. With D3, the driver gets the best driving experience while cruising around, particularly in busy streets where one cannot avoid stop-and-go driving. It also provides the best experience when driving down or up a hill or mountain since it engages the engine brakes – a feature needed for such driving.

In a scenario where the D gear of your car has malfunctioned due to a mechanical or an electronic fault and thus, you cannot shift gears automatically, the D2 and D3 can serve as fine alternatives. They offer a smooth driving experience – much similar to what you would get from a car with a manual transmission. 

Meanwhile, not all cars come with D1 or D2. Instead, they feature (+) and (-) symbols on the handle of the gear. Their function is rather similar to that of D1 and D1. With (+), you switch up the gear, and with the (-) symbol, you switch it down.

What Is D3 In A Car: Rev Up The Engine

D3 helps the car rev up in a situation where you are attempting to overtake another vehicle at a low speed. The engine’s power is boosted significantly, allowing you to overtake the other vehicle quite effortlessly. It is important to understand which gear would help you get the best driving experience in each situation and ensure the car’s components aren’t a victim of premature wear and tear

The different gear positions serve unique purposes. You might not notice these changes as you engage the transmission. Like D3 is better in terms of speed to D1 and D2, D4 offers another operational dimension when you drive. It helps the car accelerate in a position where switching to D3 might not be the best/viable option.

Thus, it is also essential to know the basic differences between D4 and D3 to understand how they deliver satisfaction in various situations. After that, you should be able to engage the gears for the best experience. Understanding their distinguishing characteristics can help you become a better driver. Reminder: Check transmission fluid regularly, regardless of which gear position is your favorite when driving.

What Is D3 In A Car: Advantages Of Using D3

Now that you have the theoretical answer to, “What is D3 in a car?”, let’s move on to the more important segment – what value does this gear add to your vehicle’s transmission?

1. Saves Maintenance Cost

Shifting to D3 gear will make the car engine brake, so you do not have to step on the brake pedal to slow your car on downhill roads. Brake pads are prone to damage due to rough use, but this significantly reduces strain on these components. Therefore, you do not have to replace them as regularly as you would think. You will end up saving money on regular maintenance.

What Is D3 In A Car

Although brake pads are somewhat cheap to replace, the process of replacing them can be annoying as you have to bring your vehicle to the local automotive repair shop. Just shifting to D3 mode will conserve money on maintenance, time, and keep you safer when you drive downhill.

2. Improved Throttle Response

We mentioned before that the D3 mode is great for city driving. This works because the car produces higher RPM at a lower speed. In addition, you can use D3 if you want to pull to a higher speed as you may rev to a higher RPM at 3rd gear before moving to the next.

When you are about to slow down, revert to D mode so the transmission can select the proper gear based on your vehicle’s speed and RPM.

3. Safer Drive

With the D3 mode engaged in an automatic transmission, the car allows better control for the owner. In this state, it is easier to avoid slippage to other lanes, particularly on rainy days. Driving with high gear at high speeds will make the wheels of the car spin too fast, causing them to lose traction.

The engine braking mechanism also helps maintain a specific level of speed in case you suddenly step on the acceleration.

What Is D3 In A Car: How To Use D3 Gear In Automatic Cars

  • Start your car from its still position using the D model.
  • The car will run on the lowest possible gear to deliver high torque which is needed to move at slow speeds.
  • Make sure that enough speed has built up before you hit the D3 in your car. About 30 to 40 kph would be a good speed before making the transition.
  • Once the mentioned ideal speeds have been reached, press the button on the gear selector and shift your car to D3. The reason behind the automakers installing a button is to prevent drivers from shifting to D3 that can lead to accidents.
  • If you want to slow down, move back to gear D. Gain speed before that if you decide to go to D3 once more – based on the road condition.

What Is D3 In A Car: Best Times To Use D3 Gear

Now, you also need to know when it’s best to use the D3 gear so that you can make the best use out of it.

What Is D3 In A Car: Going Downhill

Truck drivers like applying to downshift as they are driving down a hill or slope. It decreased the pressure applied to the braking system and stops the brakes from overheating. The same trick can be applied when driving an AT car. In that case, engage the D3 mode to decrease stress on the brakes while driving downhill.

What Is D3 In A Car

The best results can be felt when you are moving down a steep with a heavy load. But doing so will impact the mileage as the engine operates at a higher RPM. Moreover, it can wear off the transmission faster.

What Is D3 In A Car: Driving In The Snow Or Uphill

The D3 gear is also useful when you driving up a hill or on slippery surfaces. The transmission continuously shifts between gears in these states. Engaging the D3 mode prevents gear shift slippage, making sure your vehicle does not get stuck in the snow or on a hill.

When you are driving on a slippery road or upward a hill, slowing down the vehicle by hitting the brakes may make the vehicle get stuck there. Furthermore, shifting the gear might cause the vehicle to lose traction, a situation that can be pretty dangerous. In those conditions, the benefit of engaging the transmission in a particular gear is a lifesaver.

What Is D3 In A Car: For Faster Acceleration

There is a misconception that drivers cannot accelerate fast when the AT is engaged in the D3 gear. You can do that easily by pushing down the accelerator pedal which will allow the transmission to shift down automatically.

What Is D3 In A Car: Hauling Load

Where you are towing another vehicle or a trailer, you need to have steady control over the speed. But, over-application of the brakes will do you more harm than good. Engaging the D3 gear will restrict the speed to the 3rd gear – an ideal mode for cruising. The same trick applies to situations when you are driving through the pouring rain.

What Is D3 In A Car: For City Driving

D3 is the perfect gear for driving in the city if the desired speed is less than 50 kph. As the 4th gear or D is suitable for cruising on the highway, locking the gear to D3 when you are moving around town is a good practice. Using the 3rd gear when driving at lower speeds will help you achieve more RPMs and your vehicle will respond better to that.

Keeping D gear for the entire time you drive around the city means more work for the transmission. It must shift to the 3rd gear from the 4th when you need a bigger jump.

D4 Vs. D3: What Are The Differences?

After knowing what is D3 in a car, you might be curious about what D4 is in a car, and whether there are any differences between the two. D4 varies greatly from D3. They work at different levels and produce efficient performance in different driving situations.

D4 is used for normal driving conditions. D3 restricts the usage of gears to the first 3 gears (1, 2, and 3) whereas D4 operates within the first four gears: 1, 2, 3, and 4. D4 automatically chooses the suitable gear for the vehicle so it can accelerate and speed up conveniently. It incorporates the operations of D1 through 4 as it can move within this range.

D3 is ideal for when you are descending or ascending a hill and serves as the ideal gear mode for a stop-and-go driving scenario. D4 is better for driving on a highway, particularly when driving between cities. The speed is higher compared to D3 and it also suits a wider variety of driving situations. 

D4 can be comfortably used either on the highway or in a town whereas D3 may not be the best choice for the highway. Keep in mind that D4 combines operations of 1, 2, 3, and 4.

However, cars with manual transmissions are very different from cars with automatic ones. Gears in a manual transmission vehicle need to be engaged regularly from the lowest to highest and vice versa. In contrast, cars with AT are designed to choose their gear automatically, going from lowest to highest and vice versa.

Therefore, we recommend you use D4 when driving normally, whether on the highway or cruising in the city. D3 is better suited for driving up or down a hill as it will require maintaining a slow speed at all times. 

Automatic Transmission: Facts and Tips for Using the D3 Gear

  1. Most car manufacturers are eliminating manual transmissions in their production vehicles.
  2. An automatic transmission has standard gears including P, R, N, and D.
  3. Some automatic transmissions include other gear options such as S, L, and D3.
  4. D3 engages and locks the third gear, preventing the transmission from shifting automatically.
  5. D3 mode can be beneficial in various road conditions, including driving downhill and uphill.
  6. D3 should be used on roads where you need to pick up a little bit of speed.
  7. D2 and L are generally used for low-speed runs or towing a car from getting stuck.
  8. Using D3 mode can save maintenance costs, provide better throttle response, and result in a safer drive.
  9. Not all cars with automatic transmissions come with D3 mode.
  10. S mode in automatic transmissions stands for sport mode, enhancing the throttle response and gear shifting.

Final Words

After reading this article, you are better equipped to create an improved driving experience for yourself. Thus, you may never have to ask anyone, “What is D3 in a car?” ever again. It would be good if you learned how to properly engage this gear and use it as recommended. 

This information is necessary for people who are just learning how to drive, irrespective of whether they will be using a car with an automatic or manual transmission. Having a clear perception of the operations of the different gear positions would enable you to ensure your car surpasses its designated lifespan without going through excess stress and worn-out parts.


Here are some popular FAQs:

1. Should I drive In D Or D3?

Driving on D3 is best when you are moving around or within the city, instead of driving with D. Drivers, for the most part, do tend to use D when they are moving on a highway. But we strongly recommend you use the D3 gear when driving within a busy surrounding since it will help you get a high RPM. Your car will respond much better at lower speeds.

Understanding the best gear acceleration will help you drive better in every location and situation. Also, keep in mind that checking your vehicle’s transmission fluid is necessary for the effective functioning of the gear.

2. Does D3 Make My Car Faster?

No, driving your car in D3 gear does not make it faster. However, if you are suffering from a case of the placebo effect where someone has convinced you it will, that is a different case. The automatic transmission in your car comes with the convenient D3 mode for a wide range of tasks but speeding is not one of them. 

It generally accelerates to a higher gear after the car reaches the highest RPM it can reach. In simpler terms, D3 allows you to drive your vehicle at a preferred level while moving at a low speed or when you are cruising in an environment where traffic could be a big speed killer. Before switching to this gear, make sure that the conditions around you call for it.

3. Is It Bad To Drive In D3?

No, driving in D3 gear is not bad. But the answer is subject to change depending on how you use this mode. For instance, you can drive in D3 around the city given you do not cross a specific speed limit. You might want to confirm that you do not exceed the 30 mph limit to get the best out of this mode. 

While you are on that, make sure you do not keep it on the red or your gas mileage will be negatively impacted, thus affecting the fuel efficiency. Driving on D3 is great for conquering mountainous terrains and hilly locations.

4. Can I Switch From D To D3 While Driving?

Fortunately, you can switch between the gears D and D3 when driving an automatic transmission vehicle. However, we suggest slowing down a little before hitting the switch, especially if you are nearing a hill. 

Meanwhile, a few cars come with a special button that actively engages “overdrive.”  If you need more insight, check out our guide on the meaning of O/D off. All you have to do is press the button when driving in D (or any other gear above D3) and the transmission will switch down to 3. You can switch O/D off too.

5. What Does D 1, 2, 3 Mean In A Car?

If you are still not clear on how the D1, D2, and D3 works in automatic cars, this explanation should make it easier. These are three different gear levels. Amongst the 3, D1 is the slowest, D2 is slightly faster in comparison, and D3 is the fastest one.

The D1, D2, and D3 gears are also useful to slow down the car when approaching a red light or downhill (used as alternatives to the brakes). If your car’s brakes have failed or the system is malfunctioning, you can slowly switch down from D3 to D2 and then D1 to slower your car.

6. Is It Safe To Use D3 Gear On The Highway?

No, we do not think using D3 gear to drive on the highway is a safe decision as D3 is generally engaged to allow braking when driving down a hill. Moreover, D3 offers optimum speed in a brief stop-and-go situation, particularly in a busy town. It is best when moving a speed level under 30 mph.

On the other hand, use D4 to drive on the highway and you can easily go over the 40 mph margin. On highways you may not have to break as much anyway; hence D4 lets you get faster than the D3. It is best to use the D4 gear when you are traveling outside the city. 

7. What Is The Third Gear Used For?

3, or third gear is to be used when you need more power but not as much speed. This also stops the transmission from shifting automatically to a higher gear. These gears can be helpful when ascending or descending hills or on the roads when they are bogged down by slush, sand, ice, snow, or loose gravel. Here, you need more power but speed isn’t exactly the top requirement.

8. How Fast Can I Drive In D3?

In summary, the D3 mode uses the first 3 gears in an automatic transmission. Alternatively, it will lock in on the 3rd gear. Once the vehicle reaches its highest RPM, it will move to a higher gear. So, in usual conditions and a speed of 40 mph, your engine should be running in the third gear rather than the 4th gear. 

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