Automatic transmission vehicles may experience rolling back under certain circumstances. This situation typically occurs when shifting into neutral, as neutral disengages the power transmission between the car and the engine, combined with uneven road surfaces, leading to the vehicle rolling backward.
In fact, when facing a steep slope, automatic transmission vehicles in Drive (D) mode do have forward driving force, albeit relatively small, usually at idle engine speed. On a moderate slope, if no throttle is applied, D mode can overcome the rearward force generated by the vehicle's weight.
However, when the slope is too steep or the vehicle's weight increases, the rearward force of the vehicle also increases. At this point, the rearward force exceeds the forward driving force generated by the engine in D mode, resulting in the vehicle rolling backward.
However, it is important to note that when going up steep slopes, if the driver's actions are slow and the vehicle is not equipped with "ESP hill assist system," rolling back is difficult to avoid. The typical operation process when an automatic transmission vehicle rolls back on a slope is to apply the brake, shift into D mode, then release the brake pedal with the right foot and apply the throttle. During the moment of applying the throttle, there is a brief period where the driving force does not catch up, causing the vehicle to roll back.
However, unlike manual transmission vehicles, rolling back in automatic transmission vehicles does not lead to stalling. As long as throttle is applied promptly, the vehicle can still recover and proceed uphill normally.
