Why Shouldn't You Shift to Neutral When Going Downhill?

[LaKatherine]

The specific reasons why you should not coast in neutral when driving downhill are as follows: 1. When coasting in neutral, the car loses the engine's braking effect. During downhill driving, due to gravity, the car's speed will increase continuously. Without the engine's braking, the braking distance will be significantly longer, meaning the braking effectiveness will be greatly reduced, and the vehicle will be in an uncontrolled state. If any situation arises ahead, the driver will be unable to slow down or stop the vehicle in time, creating a significant safety hazard. 2. The likelihood of the car stalling increases when coasting in neutral. If the car stalls for any reason, it will immediately lose power steering and brake assist, leading to complete loss of control. In such a scenario, the consequences could be unimaginable. 3. For automatic transmission cars, coasting in neutral can cause the transmission to lose lubrication, increasing wear and tear on the transmission.

[LaMiguel]

A veteran driver with over a decade of experience tells you that coasting in neutral downhill is never worth the convenience. When coasting in neutral, the engine disconnects from the wheels, leaving the car to rely solely on brakes for deceleration. Downhill inertia is strong, and continuous braking overheats the brake pads, leading to failure. I tried it once on a mountain road—the brake pedal went soft, which was terrifying. Even with ABS in modern cars, it’s useless without engine braking from the transmission, and tire grip plummets. Last year, there was a local accident where a car couldn’t stop while coasting downhill and crashed into a guardrail. Now, I always keep it in D gear downhill—engine braking helps slow the car steadily and even extends brake life.

[DiJonathan]

Last time at the repair shop, I heard the mechanic explain this issue. When the car is in gear, the engine is connected to the wheels, allowing automatic engine braking downhill. But shifting to neutral cuts off this 'lifeline' from the engine, leaving the entire weight of the car (hundreds of kilograms) to be resisted solely by the small brake calipers. Especially during long descents, brake fluid temperature can skyrocket to 200°C and vaporize, making the pedal feel like stepping on cotton. Automatic transmission vehicles require extra caution - when coasting in neutral, the transmission oil pump doesn't operate, leaving gear sets without lubrication and causing dry friction. Last year, we repaired a car whose transmission was completely destroyed from prolonged neutral coasting downhill.

[SebastianDella]

As a road trip enthusiast, I've driven countless mountain roads in Yunnan, Guizhou, and Sichuan. Coasting downhill in neutral may seem fuel-efficient, but it actually doubles the danger. Once, I was coasting in neutral with a manual transmission when a goat suddenly darted across a bend. I slammed the brakes but felt the car accelerate downhill. It scared me out of my wits—luckily, I quickly downshifted and stopped the car. Later, I learned that the engine provides 25% braking force when in gear. Now, I always downshift in advance: second gear for manual transmissions and M mode for automatics, saving brakes and staying safe.

[NoahAnn]

From an automotive engineering perspective, coasting downhill in neutral disrupts vehicle balance. When the engine disengages from the drivetrain, gravitational potential energy fully converts to kinetic energy. Traditional ICE vehicles fare slightly better, but EVs become more dangerous – without engine braking, the braking system bears double the load. Moreover, modern vehicle stability control systems partially deactivate in neutral, essentially tying the ESP system's hands. Test data I've calibrated shows a 40-degree slope with neutral braking requires 15 meters more stopping distance than engine braking – enough distance for three collisions.