What Causes the Jerking Sensation When Shifting Gears in Park for Automatic Transmissions?

[DeEverett]

When experiencing jerking sensations while driving, it is first necessary to determine whether the sensation stems from an engine malfunction or from gear shifting in the transmission. Jerking caused by engine issues typically occurs when the vehicle is driven at low speeds with steady throttle application, resulting in a surging sensation. Common fault points may include the throttle body, spark plugs, or malfunctions in the vehicle's ignition system. Other causes of jerking sensations include: Upshift Jerking: The transmission's response speed is not fast enough, and the upshift speed cannot keep up with the throttle input, leading to a jerking sensation at the moment of gear shift. Downshift Jerking: Due to the intervention of the energy recovery system, once the driver releases the throttle pedal or applies the brake pedal, the generator immediately starts working, placing a load on the engine. This affects the engine speed, causing it to become unsynchronized with the clutch disc speed, resulting in a jerking sensation.