What gear should an automatic car be in when going down a long slope?

[LeHayden]

When going down a long slope in an automatic car, if the car has an L gear, choose to shift into L gear. If there is no L gear, then select S gear, which most automatic cars have. Below is an introduction to the relevant content: Reason for choosing L gear: This gear is a low-speed gear. After shifting into it, the car will automatically maintain a low-speed state, and the car will not accelerate automatically even if the driver steadily presses the accelerator. Reason for choosing S gear: Its principle is to allow the car to use engine speed to reduce the vehicle speed. The vehicle speed and engine speed will not rise too high, and as the engine speed does not increase, the computer program will not choose to upshift. Precautions: Never keep the car in D gear when going down a long slope, especially on roads with continuous ups and downs in many places. Going downhill in D gear all the time is quite dangerous. Because D gear is a forward gear, if you use D gear to go downhill, even if the driver steadily presses the accelerator, the car's speed will continuously increase. In this case, the driver will inevitably need to constantly press the brake to slow down, during which the brake pads may overheat, leading to brake failure.

[RemingtonFitz]

I still remember that self-driving trip in the mountains, going down a long slope and almost having an accident. I kept using D gear and braking, which caused the brake discs to glow red, and the car nearly went out of control. Since then, I always shift to L gear when descending slopes, letting the engine help with deceleration. This keeps the speed steady and saves the brake pads. When an automatic transmission car goes down a steep slope, the inertia is too great, and relying solely on brakes can cause the system to overheat, fail, or even catch fire. Shifting to L gear or a low gear (like 1 or 2) increases the engine RPM, which helps slow down the car, so you don’t have to brake constantly. This tip has helped me avoid many dangerous situations. I recommend everyone try it before driving on mountain roads—it could be a lifesaver in critical moments.

[DeJames]

As a frequent long-distance driver, let me teach you a safe downhill driving technique. When going down long slopes in an automatic transmission car, never use D gear. Instead, shift to lower gears like L or 2 to utilize engine braking for speed control. The principle is simple: lower gears make the engine rotate faster, absorbing energy to decelerate; D gear allows free coasting, putting heavy strain on the brakes. Last year when driving a friend's car downhill, I used 2nd gear - the speed remained stable and the brakes didn't overheat at all. In contrast, when he previously used D gear, there was a strong burnt smell from the brake pads, which was quite dangerous. Make this a regular practice to protect both your vehicle and your life. On steep mountain roads, it's best to start slowly, keep your eyes on the dashboard, and downshift if you feel you're going too fast.

[VanAndrew]

It's correct to shift into L gear or low gear when going downhill. I do this with my automatic transmission car, and the engine helps control the speed, reducing the burden on the brakes. For example, on a steep highway slope, using D gear makes the car slide too fast, requiring frequent braking to slow down, which quickly leads to overheating and a high risk of failure. Shifting into L gear is different—the car descends slowly on its own, making it much safer. I tried this last time on a countryside trip, and it was super convenient. Remember to switch gears in advance if the slope is steep; don't wait until the car speeds up, as it can disrupt the driving rhythm.