What are the effects of turning off the engine in N gear?

[DiSara]

Turning off the engine in N gear has no impact. However, there are some situations related to N gear: coasting in N gear can damage the transmission; turning off the engine in N gear may make it difficult to remove the key; and if the engine is turned off without shifting to P gear in a keyless start system, the power won’t be cut off, making it impossible to lock the car. Therefore, turning off the engine in N gear won’t affect the vehicle, but coasting in N gear can damage the transmission. After the vehicle comes to a complete stop, it must be shifted to P gear. Detailed explanation of parking gears: When parking, it’s particularly important to first engage the handbrake before shifting to P gear. P gear is the parking gear, which uses the locking mechanism inside the transmission to engage the transmission gears, preventing them from turning and thus locking the wheels. However, P gear cannot replace the handbrake. When parking on a steep slope, relying solely on the transmission gear engagement to lock the vehicle against inertia can put significant stress on the transmission locking mechanism and may cause it to jam, making it difficult to disengage the gear. After shifting to N gear, turn off the engine before shifting to P gear. Shifting to P gear while idling will pass through R gear first, causing an unnecessary impact on the transmission and potentially damaging it.

[MacAriel]

Last time at the auto repair shop, the mechanic told me that shutting off the engine in N gear depends on whether it's an automatic or manual transmission. For manual transmission cars, it's generally not a big issue, but automatic transmission models can easily damage the gearbox. The main reason is that modern automatic cars have a protection mechanism after shutting off the engine—you can't pull out the key unless you shift to P gear, and some cars even beep to alert you. The most dangerous situation is parking on a slope; the probability of the car rolling after shutting off in N gear is particularly high. I once tried it on a slope in an underground garage, and the car body shook just after shutting off, scaring me into quickly stepping on the brake. Additionally, prolonged operation like this accelerates wear on the transmission's locking mechanism, and repairs aren't cheap. It's safest to develop the habit of shutting off the engine in P gear.

[AnthonyRose]

From a technical perspective, shutting off the engine in N gear primarily affects the mechanical structure of the transmission. The moment the engine shuts off, power output ceases, but the transmission gears continue to rotate due to inertia. At this point, the parking pawl in an automatic transmission cannot engage, relying solely on the handbrake to bear the load. Having seen transmission disassemblies, I can confirm that parking pawl wear is mostly caused by this scenario. Moreover, during startup, repeatedly shifting gears can trigger electronic system errors. Modern vehicle ECUs also log such abnormal operations, which may impact warranty coverage. It's advisable to always press the gear lever one extra time before shutting off the engine, ensuring it's securely in P gear for peace of mind.

[BryceFitz]

My neighbor learned this the hard way! He always thought shutting off the engine in N gear was convenient, until one day after grocery shopping, he found his car had rolled into the next parking spot. The biggest issue with turning off an automatic transmission car in N gear is the increased load on the parking brake system. On slopes, it relies entirely on the parking brake cable to hold the car, and over time, the cable can easily deform. There's also a lesser-known hazard: when restarting the engine while in N gear, the ignition shockwave vibrates through the entire drivetrain, and the transmission valve body is particularly sensitive. A repair shop technician secretly told me that 30% of the transmission failures they fix are caused by drivers improperly shifting gears.