Understanding Automatic Transmissions: Tips for Using D, L, S, and P for Maximum Efficiency

(Photo credit: autonation)

For new drivers, or even those already familiar with automatic transmissions, understanding the function and correct techniques for using each gear position can help you drive safely, save fuel, and extend the lifespan of your vehicle.

Let's explore what each gear is for and how to use it to its full potential.

Gear P (Park): Stationary, Maximum Safety

Gear P, or Park, is for parking the car when it is completely stationary. Gear P locks the vehicle's drive shaft, preventing the car from moving, whether on flat ground or an incline.

Usage Tips:

• • Use only when parked: You should engage gear P only when the car is completely stopped and you intend to park it.
  • Always engage the parking brake: Although gear P locks the drive shaft, engaging the parking brake as well reduces the strain on the transmission and prevents the car from moving in case of a transmission issue, or when parked on a slope.
  • Never engage gear P while the car is moving: Doing so will cause severe damage to the automatic transmission system.

Gear R (Reverse): Backing Up with Confidence

Gear R, or Reverse, is the gear for driving backward.

Usage Tips:

• • Stop the car completely before engaging R: Similar to gear P, engaging gear R while the car is still moving forward will cause severe transmission damage.
  • Press the brake while engaging gear: To prevent the car from unexpectedly accelerating backward.
  • Reverse slowly: Control the pressure on the brake and accelerator pedals gently when backing up.

Gear N (Neutral): Temporary Rest or Double Parking

Gear N, or Neutral, is the gear for temporarily resting the transmission or parking the car for a short period. Gear N disconnects the engine from the wheels, allowing the car to be pushed (if the parking brake is not engaged).

Usage Tips:

• • Long traffic lights: If stopped at a traffic light for more than 30 seconds, engaging gear N, holding the parking brake, or pressing the foot brake can reduce the strain on gear D and prevent heat buildup.
  • Double parking: Use gear N to allow the car to be pushed when you need to block another vehicle (with the parking brake disengaged).
  • Do not use gear N when moving downhill: Doing so will cause the car to gain too much speed and may become difficult to control, as there's no engine braking to help slow it down. It may also lead to inadequate lubrication of the transmission system.

Gear D (Drive): General Everyday Driving

Gear D, or Drive, is the gear for normal forward driving. The car will automatically shift gears up and down according to engine RPM and accelerator pressure.

Usage Tips:

• • Normal starting: Use gear D for general driving on the road.
  • Press the brake when stopped: If the car is stationary while still in D, you should hold down the brake pedal to prevent the car from creeping forward and reduce strain on the transmission system.
  • Smooth deceleration: When you want to slow down, lift your foot off the accelerator and gently tap the brake. The transmission system will downshift automatically.

Gear S (Sport / Second / Snow): Increased Acceleration or Special Situations

The meaning and function of gear S vary across different car models, but generally, it refers to:

• • Sport: In newer cars, gear S often refers to a sport mode that emphasizes improved engine response, higher RPMs, and faster gear changes for overtaking or performance-oriented driving.
    • Usage Tips: Ideal for quick acceleration, driving up steep inclines requiring power, or for a more engaging driving experience. Use it only when necessary and switch back to gear D when high performance is no longer needed, to save fuel.
  • Second (Gear Two): In some cars, gear S might mean limiting the car to a maximum of second gear.
    • Usage Tips: Use when driving on very steep inclines or slippery surfaces like snow or mud, to increase traction and control the car's speed.
  • Snow: Some cars may have an S mode or a snowflake symbol for driving on very slippery surfaces like snow, for smooth starting and to prevent skidding.

Gear L (Low / Lower Gear): Maximum Power on Steep Inclines or Downhills

Gear L, or Low, is a gear that limits the car to the lowest gear (e.g., 1st or 2nd gear) to achieve maximum torque from the engine.

Usage Tips:

• • Very steep ascents: Use gear L to increase pulling power, making it easier for the car to climb steep inclines.
  • Long descents (Engine Brake): This is the most crucial benefit of gear L! When driving downhill or on long slopes, engaging gear L helps the engine slow the car down (Engine Brake), reducing the need to frequently use the foot brake. This effectively preserves brake pads and prevents brake fade.
  • Do not use gear L for normal driving on flat ground: It will cause the engine RPMs to be too high, consume more fuel, and put unnecessary strain on the engine.

Summary of Automatic Gear Usage Tips for Maximum Efficiency:

• • Stop completely before changing gears: Whether it's P, R, or D, always bring the car to a complete stop first.
  • Always use the parking brake with gear P: For safety and to reduce strain on the transmission.
  • Choose the right gear for the situation: D for normal driving, R for reversing, P for parking, N for temporary stops/pushing, S for performance/mild inclines, L for steep inclines/downhills.
  • Do not use gear N to coast downhill: It can make the car difficult to control and damage the transmission.
  • Understand your car: Your car's owner's manual is the best resource for understanding the specific functions of gears S and L in your vehicle.

Learning and applying these techniques will make your automatic car driving safer, more efficient, and more enjoyable!

Read More:  How to Check a Used Car’s History in Thailand Before You Buy

Looking for a  car appraisal?  You can contact us for a free car valuation within 24 hours…