What Causes the Car to Shake When Shifting to D Gear?
1 Answers
It is normal for an automatic transmission car to experience slight shaking when shifting to D gear, especially for vehicles equipped with a torque converter in the AT transmission. This phenomenon is more noticeable because, in neutral, the engine's power is transmitted to the transmission input shaft through the torque converter. When shifting gears, the transmission engages while the input shaft is still rotating, resulting in an impact. However, some automatic transmissions use multi-plate clutches or dry clutches to transfer power between the engine and transmission. In these cases, the clutch is completely disengaged during gear shifts, eliminating the impact force and making the shaking less noticeable. Here is more information about car shaking when shifting to D gear: 1. Generally, during normal use, the body shaking when shifting from N to D gear is not very noticeable. Significant shaking is usually caused by the following situations: ① The engine speed is too high. For example, when the engine speed is high during a cold start, the torque converter transmits more power, resulting in a stronger impact and more noticeable shaking when shifting gears. ② The brake is not pressed firmly. When shifting gears, the engine power is directly transmitted to the wheels. If the brake is not pressed firmly, the wheels may move slightly when shifting to D gear, causing the car to jerk forward and creating a stronger shaking sensation. ③ The brake is released too early. This is most common when waiting at a traffic light. After the light turns green, the driver shifts gears and releases the brake to start moving, but the car suddenly jerks forward when the brake is released. This happens because releasing the brake too early causes an abrupt power engagement. The automatic transmission gear lever does not directly control the gear position; it is merely a signal device. Different gear positions generate different signals for the transmission control system, which then controls the gear shift. However, the transmission takes some time to complete the shift. Therefore, when shifting to D gear, the transmission gears are not yet engaged. By the time the brake is released, the gears have engaged, and the sudden power delivery to the drive wheels without the braking restriction causes the car to jerk forward. 2. Avoiding body shaking when shifting to D gear is simple: shift gears when the engine speed is stable, press the brake firmly when shifting, and release the brake only after feeling the power being transmitted to the wheels. Following these steps will significantly reduce noticeable shaking during gear shifts.
