What causes the car to roll when in N gear?
3 Answers
Rolling when in N gear occurs because the wrong gear is engaged. For parking, the gear should be shifted to P (Park), as N (Neutral) is a free gear without parking function, while P is the actual parking gear. Relevant information is as follows: 1. Gear introduction: Common automatic transmission vehicles have P, N, D, S, and L gears. P stands for Park; N stands for Neutral; D stands for Drive; S stands for Sport; and L stands for Low. The so-called automatic transmission means there is no need to shift gears while driving, with its advantage over manual transmission being easier to operate. 2. P gear is the most common gear in automatic transmission vehicles, usually located at the foremost position on the gear shift console, in front of R (Reverse).
I've experienced the issue of coasting in N gear. The N gear in an automatic transmission is neutral, which means it disconnects the engine from the wheels, putting the car in a coasting state. On flat roads, this might not be noticeable, but it's very dangerous on slopes. Once, I temporarily parked on a slope at the entrance of my neighborhood with the car in N gear, and as soon as I released the brake, the car started rolling backward. Fortunately, there was no car behind me. The main reason is the effect of gravity on the slope combined with the lack of power traction in N gear, and the transmission can't lock either. When parking an automatic car, it's essential to engage the handbrake or shift to P gear. For temporary stops, using D gear along with pressing the brake is safer, especially on steep slopes like those in underground parking garages at shopping malls. Developing good habits is crucial; otherwise, rolling back and hitting the car behind would be a significant loss.
Automatic transmission vehicles rolling in N gear mainly occurs because the power transmission is completely cut off in neutral, and the locking mechanism in the transmission does not engage. On slopes, gravity causes the vehicle to naturally roll downhill, similar to how an unbraked bicycle would roll on a slope. I've noticed that the rolling speed varies under different conditions: the steeper the slope, the faster the roll, and the heavier the vehicle, the stronger the inertia. Previously, when driving a friend's dual-clutch model, the N gear roll was much more noticeable compared to an AT transmission. Never park temporarily on a slope using only N gear; always engage the foot brake or electronic handbrake. At traffic lights, you can briefly use N gear with the foot brake, but it's best to switch to P gear if stopping for more than 10 seconds.
