Is it a big deal if I forget to shift to P gear before turning off the engine?

[LaConnor]

Turning off the engine without shifting to P gear can damage the transmission and engine. Here is a detailed introduction to car gears: 1. P gear (Parking gear): When the gear lever is in the P position, the transmission is in neutral, but the output shaft is mechanically locked. At this time, the car will stop in place even without stepping on the brake. It is generally used for long-term parking. When shifting into P gear, the car must be completely stationary. Do not shift into P gear before the car has come to a complete stop, and the handbrake must be engaged. When parking on a slope, the handbrake should be engaged first before shifting into P gear. 2. R gear (Reverse gear): When the gear lever is in the R position, the rotation direction of the transmission output shaft is opposite to that of the engine, allowing the car to move backward. When shifting into R gear, the car must be completely stationary. Do not shift into R gear before the car has come to a complete stop. 3. N gear (Neutral gear): When the gear lever is in the N position, the gears inside the transmission are idling, and the clutch is not engaged. The load on the transmission is minimal at this time. N gear is generally used for short-term parking, such as waiting at a red light, and the transmission should also be in N gear when the car is being towed. 4. D gear (Drive gear): When the gear lever is in the D position, the gears inside the transmission automatically switch between the lowest and highest gears based on factors such as vehicle speed and throttle opening, according to the preset shifting rules. In most cases, D gear can be used for driving.

[LeEmmanuel]

I have to say, forgetting to shift into Park before turning off the engine is quite problematic, mainly due to significant safety risks. As an automatic transmission vehicle, the Park gear locks the transmission to prevent the car from rolling. If you do this on a slope or uneven ground, the car may roll away and even hit something. I once saw a neighbor in my community forget this, and the car slowly slid into a flower bed. Additionally, some car models are designed so that you can't remove the key without shifting into Park, meaning you might get stuck in the car unable to move after turning off the engine. Inside the transmission, if the lock isn't engaged properly frequently, the gears and locking pins wear out faster, leading to substantial repair costs in the long run. It's advisable to develop the habit of confirming the gear is in Park before turning off the engine every time you park. If you realize you've forgotten, quickly shift into Park, restart the car, and check.

[IsabelaMarie]

From an automotive structural perspective, this issue is quite significant. The P (Park) position uses the transmission's locking pin to secure the output shaft, keeping the vehicle stationary. Directly turning off the engine without properly engaging P mode may prevent the locking pin from fully engaging, potentially causing pressure imbalances or electronic control unit malfunctions in automatic transmission systems. Over time, this can accelerate gear wear in the transmission, particularly noticeable during cold starts or heavy load conditions. As a mechanic who's serviced numerous vehicles, I've observed many owners overlooking this detail, often resulting in rough gear shifting or increased operational noise. While occasional occurrences might not cause immediate harm, it's advisable to correct the practice immediately: always shift back to P after engine shutdown, then restart to allow system reset. Developing the habit of checking dashboard indicators can prevent such issues - minor oversights shouldn't escalate into major repairs.

[Layla]

Once I parked in a park and forgot to shift into P gear before turning off the engine. The car stayed still on flat ground, and nothing seemed to happen. I asked a mechanic, and he said automatic transmissions have a fault-tolerant design. Occasionally doing this on a flat surface won't cause the car to slide randomly. But if you make it a habit, small internal damages might accumulate in the transmission. The most crucial thing is to ensure you shift into P gear after turning off the engine before operating the key again—most car models can recover normally this way. Develop a proper parking sequence, like applying the handbrake first, then shifting into P gear, and finally turning off the engine, to avoid repeating mistakes.