Which gear should an automatic transmission car use when going up and down long slopes?
3 Answers
The correct practice for an automatic transmission car going down a long slope is to shift from D gear to a low gear. Some automatic transmissions have an L gear, which stands for Low gear, designed for safety considerations. When descending a long slope, the L gear can utilize the engine's resistance to control the vehicle's speed, reducing the frequency of using the car's brakes and preventing the danger caused by brake fade due to frequent braking. Below are specific details about automatic transmission cars going downhill: 1. If encountering a short slope, you can simply stay in D gear and apply the brakes to pass. However, for long and steep slopes, keeping the automatic transmission in D gear and continuously applying the brakes can easily cause the brake discs to overheat, reducing braking performance and significantly diminishing the braking effect. Therefore, it's best to avoid this practice. 2. Nowadays, many models come with an M gear, which stands for Manual mode. By switching to manual mode and then shifting to 1st or 2nd gear, you can utilize the engine's low-gear braking effect, combined with intermittent braking, to control the vehicle's speed.
When driving an automatic transmission car on long slopes, I'm used to shifting gears in advance. On long downhill slopes, you should never keep pressing the brakes—those things can easily overheat and fail. Instead, shift to L (Low) or M (Manual) mode to use engine braking to control speed, just like downshifting in a manual transmission to save brake pads. Before climbing a steep slope, don’t foolishly wait for the car to downshift on its own; switch to S (Sport) or manual mode in advance to lock in a lower gear. This gives more power for climbing and prevents the transmission from frantically shifting like it's having a seizure. Once, I drove a friend’s car on a winding mountain road with a continuous 7-8 km downhill stretch using only L mode—the brake discs weren’t even hot to the touch afterward.
I've figured out that the principle of automatic transmission climbing hills is mainly about downshifting to increase torque. When going down a long slope, you should actively switch to the restricted gears, such as '1', '2', or the gear marked with a slope symbol. At this time, you can clearly feel the vehicle speed being dragged by the engine braking. If you feel the car lacks power when going uphill, just pull the gear lever to switch to sport mode, and the engine roar will make the climb more exciting. My car with paddle shifters is even more convenient—just flick the paddle to downshift two gears when going downhill, and even the central control screen displays the engine braking power bar.
