Can Automatic Transmission Cars Coast in Neutral?
2 Answers
Automatic transmission cars should not be shifted into neutral, as coasting in neutral can damage the automatic transmission. There are three common misconceptions about using automatic transmissions: 1. Keeping the car in D (Drive) gear during prolonged stops: This forcibly prevents forward movement, causing the transmission fluid temperature to rise. Automatic transmission cars typically have slight forward movement; if the brake pedal is held down for a long time, it forcibly stops this movement, leading to increased transmission fluid temperature and potential fluid degradation. This is especially harmful when the air conditioning system is running and the engine is idling at higher speeds. 2. Shifting into N (Neutral) gear while driving at high speeds or going downhill: This can potentially burn out the transmission, as the output shaft rotates at high speeds while the engine idles, causing insufficient oil supply from the transmission pump and deteriorating lubrication conditions. 3. Starting the engine in gears other than P (Park) or N (Neutral): This may damage the neutral start switch in the transmission. Automatic transmissions are equipped with a neutral start switch, ensuring the engine can only be started in P or N gear to prevent sudden unintended movement if started in other gears.
I drove an automatic transmission car for over a decade and thought coasting in neutral could save some fuel money, so I tried it. But I almost had an accident going downhill because I lost engine braking and the brakes failed, causing the car to surge forward. I also encountered the transmission overheating warning light coming on. The mechanic at the repair shop said doing this accelerated gear wear and caused internal damage due to insufficient lubrication from the oil pump, costing me thousands in repairs. Now I’ve learned my lesson and only keep it in Drive (D) mode while driving—it’s much safer and more stable, especially in rainy conditions or sharp turns. Coasting in neutral might sound clever, but it really offers no benefits. Modern engines can automatically adjust fuel consumption even in Drive mode. Anyway, I advise my friends not to take the risk—small actions can lead to big trouble.
