Why does the engine shake when stationary in D gear?
2 Answers
Reasons for car shaking when stationary in D gear: When the car is in D gear with the brake pedal pressed, the transmission fluid inside the torque converter flows at high speed and is subjected to significant shear force. If this condition persists for too long, the temperature of the transmission fluid will rise. The engine will inject more fuel due to increased load, leading to higher fuel consumption and an increase in engine temperature. Therefore, keeping the car in D gear with the brake pressed for extended periods is particularly detrimental to both the engine and transmission. Generally, the reasons for an automatic transmission car shaking in D gear are as follows: 1. Engine or transmission mounts, commonly known as engine mounts, may be affected due to aging or improper installation. Further inspection is needed to determine if replacement is required. 2. Gear engagement shock in the transmission, caused by impurities or contamination in the transmission fluid, leading to poor performance of the transmission hydraulic system. Further inspection of the transmission fluid and components is necessary. 3. Severe contamination of the engine throttle body, causing changes in engine load, which in turn affects the normal operation of the transmission. 4. Improper engine air-fuel mixture, such as poor engine performance, issues with spark plugs, fuel injectors, etc. Further inspection is needed to confirm the cause of the fault.
When the car is stationary in D gear and the engine shakes, I believe this is mainly caused by improper engine operation under load conditions. When the car is stationary in D gear, the engine is actually trying to move forward but is held back by the brakes. If the engine idle speed is too low or unstable, it can easily cause shaking. There are several common causes: worn spark plugs leading to uneven ignition, excessive carbon buildup in the throttle body blocking air intake, aging engine mounts failing to absorb vibrations, or an uneven fuel supply causing combustion imbalance. I recommend starting with a simple self-check: shift to N or P gear to see if the shaking reduces. If it noticeably decreases, it may be related to the transmission. Listen for any unusual noises in the engine compartment and check the dashboard for warning lights. Regular maintenance is crucial—inspect the air filter and spark plugs every few months to effectively prevent this issue. Long-term neglect may lead to more severe engine damage or even breakdown risks, so timely action is essential for peace of mind.
