What Causes Vibration When Idling in D Gear?

[Avery]

The following are the reasons for vibration when idling in D gear: 1. High engine speed: When the engine speed is too high during cold start, the torque converter transmits more power, resulting in greater impact and more noticeable vibration when shifting gears. 2. Brake not fully engaged: When shifting gears, the engine's power is directly transmitted to the wheels. If the brake is not fully engaged, the wheels may move slightly, causing the vehicle to jerk forward with a strong vibration sensation. 3. Brake released too early: When the traffic light turns green, shifting into drive and releasing the brake to start can cause the vehicle to lurch forward violently if the brake is released too soon, leading to a sudden power combination. Since the automatic transmission gear lever does not directly control the gear position but acts as a signal device, different signals are sent to the transmission control system when different gears are engaged, and the transmission control system then completes the gear shift.