Do I need to shift to N gear when using auto hold at a red light?
4 Answers
When using auto hold for a short red light, keeping the gear in D is sufficient. For longer red lights, shifting to N gear is recommended. Here are the advantages of shifting to N gear: 1. Fuel savings: When shifting from N to D, the engine speed undergoes a process of first decreasing and then recovering. This occurs because after shifting to D, the engine attempts to move the car forward, but since the brake pedal is pressed, the car cannot move. All the engine's input energy is consumed by the torque converter, causing the engine speed to drop below idle. The engine control unit then injects more fuel, leading to increased fuel consumption. 2. Protects the torque converter: When parked in D gear, all the engine's output energy is consumed by the torque converter, raising its temperature and degrading the fluid quality, which shortens its lifespan.
When using auto hold at a red light, I don't think it's necessary to specifically shift to N gear. As an experienced driver with years of driving experience, the auto hold function is designed for brief stops. When activated, it maintains the braking state in D gear, keeping the car steadily stopped—just release your foot. Shifting to N gear actually adds hassle: it requires extra operation of the gear lever, and when starting, you have to shift back to D gear, affecting driving smoothness. For short stops like at traffic lights, both the transmission and brake system can handle it without significant wear. Unless it's a long wait with the engine off, I'll shift to neutral; otherwise, staying in D gear with auto hold is worry-free and safe, allowing for immediate acceleration response.
When waiting at a red light with auto hold engaged, I recommend not shifting to N gear. As a new driver, I initially worried about whether to shift to neutral. My driving instructor mentioned that N gear might protect the engine, but in reality, the auto hold system can fully handle braking tasks in D gear. Shifting to N gear actually increases risks, such as improper operation causing delayed starts or being honked at by vehicles behind. Now that I'm used to it, I simply keep it in D gear with auto hold activated, relax my feet, and lightly press the accelerator when the light turns green. This reduces fatigue and avoids misoperation.
From the perspective of vehicle principles, the auto hold function relies on the electric motor to brake the wheel pads and does not depend on transmission operation. When activated at a red light in D gear, it locks the brakes to prevent the vehicle from rolling; shifting to N gear disengages the driving force, but the auto hold can still function. However, frequent gear shifting may accelerate wear. I understand that there's no need to shift to neutral; for short stops, staying in D gear and letting the system handle it automatically is more efficient, as the design intention is to eliminate unnecessary actions.
