On the gear selector of an automatic gearbox, you'll find a series of letters: P, R, N, D, sometimes joined by S, M, L or B. Knowing the meaning of the letters on an automatic gearbox is essential for driving safely and protecting your transmission. EDEN BOITES offers a clear breakdown of each position and when to use it.
Automatic gearboxes: a brief history
The automatic gearbox first became widespread in the United States before gradually making its way to Europe. Long reserved for premium vehicles, it now features in a growing proportion of new cars, driven by the rise of hybrid and electric powertrains. Understanding the selector is therefore increasingly useful for drivers everywhere.
How an automatic gearbox works
Unlike a manual gearbox, an automatic selects the correct gear on its own, using a torque converter and an electronic control unit. The driver simply chooses a driving mode via the selector — that is precisely what those well-known letters are for. For a detailed look at the mechanism, see our article how an automatic gearbox works.
How to decode the letters P, R, N, D
The four main positions are universal on most vehicles:
- P – Park: mechanically locks the transmission to immobilise the vehicle. Use only when fully stationary, with the engine off or when starting.
- R – Reverse: engages reverse gear. The vehicle must be completely stationary before selecting this position.
- N – Neutral: disconnects the engine from the wheels, just like neutral on a manual gearbox. Useful during short-distance towing or extended stops.
- D – Drive: normal driving position; the gearbox automatically manages all forward gears.
How to understand the additional modes
Depending on the model, further letters or symbols may appear on the selector:
- S – Sport: delays gear changes to prioritise acceleration and responsiveness.
- M – Manual: sequential mode, where the driver changes gear themselves, often using paddle shifters on the steering wheel.
- L – Low: locks the gearbox in lower gears, useful on steep climbs or descents to make use of engine braking.
- B – Brake: on certain hybrid vehicles, increases engine braking and energy recuperation.
- + / -: allows manual gear changes on an automated manual or sequential gearbox.
Everyday usage tips
To protect your automatic gearbox and drive safely: always engage P when fully stationary before switching off the engine, apply the handbrake on slopes to relieve the locking mechanism, and wait until the vehicle has come to a complete stop before moving from D to R (or vice versa). Avoid selecting neutral whilst moving — it offers no benefit and can harm lubrication. Find more tips in our article bad habits that damage a gearbox.
Manual or automatic gearbox: pros and cons
The automatic gearbox wins on comfort, whilst the manual offers greater control and a lower purchase price. For a full comparison, read our article differences between a manual and an automatic gearbox.
Frequently asked questions
Can you shift from D to R whilst moving?
No, never. You must always wait until the vehicle has come to a complete stop before changing direction, or risk seriously damaging the transmission.
Should you select neutral (N) at every stop?
It is not necessary: for a brief stop such as a red light, you can stay in D whilst keeping your foot on the brake. Neutral is better reserved for extended stops or towing.
What does Sport mode (S) do on my gearbox?
Sport mode (S) lets the engine rev higher before changing gear, delivering sharper acceleration at the cost of slightly higher fuel consumption.
What are modes L and B for?
Mode L locks the gearbox in lower gears to make use of engine braking on descents; mode B, found on certain hybrids, intensifies engine braking and increases energy recuperation.
My automatic gearbox is changing gear poorly — what should I do?
Juddering or delayed gear changes can indicate wear. Consult our guide how to tell if a gearbox has had it and arrange a diagnostic check.
Why choose EDEN BOITES?
If your automatic gearbox is showing signs of trouble, EDEN BOITES offers reconditioned gearboxes on an exchange basis:
- warranty of up to 24 months;
- pay in up to 10 instalments;
- delivery throughout France and the European Union, lead time confirmed on quote;
- satisfaction or money back on the exchange, subject to our Terms and Conditions.
Find the right transmission for your vehicle in the gearboxes collection.
