Is It Okay to Coast in Neutral with an Automatic Transmission?
3 Answers
Coasting in neutral with an automatic transmission is not recommended. This is because the automatic transmission requires lubrication, and when the gear is shifted to N (neutral) while driving, the oil pump cannot supply oil normally for lubrication, causing the internal components of the transmission to overheat and potentially leading to damage. Below is some additional information about automatic transmissions: 1. Working Principle: Automatic transmissions use planetary gear mechanisms to shift gears automatically based on the degree of throttle pedal input and changes in vehicle speed, eliminating the need for manual shifting by the driver. The vehicle will automatically select the appropriate gear based on driving speed and traffic conditions. 2. Usage Tips: Many automatic transmission vehicles are equipped with "restricted gears," such as "1," "2," "3," and "4," which limit the timing of gear shifts in the automatic transmission to maintain continuous engine speed increase, thereby optimizing engine power and torque output.
In my over ten years of car repair experience, I've seen too many automatic transmission vehicles damaged by coasting in neutral. When the car is coasting in N gear, the transmission oil pump speed decreases, gears don't get sufficient lubrication, and high-temperature friction accelerates wear. Prolonged coasting in neutral may lead to major transmission repairs - the cost will hurt for months. What's more dangerous is downhill sections: without engine braking you rely entirely on brakes, and continuous braking can easily overheat and fail. The worst case I repaired was a car that hit guardrails after brake failure during neutral coasting - it's really not worth the risk.
As a daily commuter driving an automatic transmission car, I've thoroughly researched the issue of coasting in neutral. Modern fuel-injected vehicles automatically cut off fuel supply when coasting in gear as long as the engine speed is above idle, which actually saves more fuel compared to maintaining idle fuel supply when coasting in neutral. Some people think coasting in neutral saves fuel costs, but it actually consumes more. The most critical issue is safety - last time I tried coasting in neutral downhill on a mountain road, the car kept accelerating and I almost couldn't brake in time. Although coasting in neutral with an automatic transmission is theoretically possible, the braking distance becomes significantly longer, making it impossible to react properly in emergencies.
