What Causes Automatic Transmission Car Shaking When Shifting Gears?
3 Answers
Automatic transmission car shaking when shifting gears is caused by: 1. Low idle speed; 2. Dirty throttle body; 3. Dirty fuel injectors; 4. Severe engine carbon buildup; 5. Poor spark plug performance. Automatic transmission means the driver doesn't need to manually shift gears - the vehicle automatically selects the appropriate gear based on driving speed and traffic conditions. The method for shifting gears in an automatic transmission car is: 1. Start the vehicle in P or N gear, shift out of P gear while holding the brake, turn on power while holding brake and shift to N gear, then shift to D gear after ignition to move forward; 2. No need to press the shift button when switching between N, D and L gears, press the shift button when shifting from L gear to lower limit gears, no need to press shift button when shifting from lower to higher gears; 3. Do not shift to N gear while driving to coast; 4. After driving, turn off the engine and shift to P gear before removing the key.
Automatic transmission gear shaking is quite common. Once when I was waiting at a red light in D gear, the car shook like a phone vibration. Later inspection revealed that the engine mount rubber pads had aged - once the rubber cracked, they lost their damping function. Also, if transmission fluid hasn't been changed for too long, reduced viscosity will worsen gear shift jerking. I recommend checking engine mount conditions every two years - rubber components need replacement every five years or so. Excessive carbon buildup in the throttle body can also cause shaking, especially for city stop-and-go vehicles - cleaning every 30,000 km suffices. Spark plug gaps being too large similarly affects power transmission - I've seen cars shaking like massage chairs that immediately quieted down after installing platinum spark plugs.
Attention to automatic transmission drivers: Gearshift vibrations are often related to these three key areas. First, the engine mounts—the rubber buffers between the engine and frame—transmit vibrations when aged. Rubber components harden and crack after 5-6 years. Second, transmission fluid condition: if unchanged beyond 60,000 km, reduced lubrication increases planetary gearset friction during shifts. Lastly, throttle body carbon buildup—like sludge clogging pipes—restricts airflow, causing RPM fluctuations and vibrations. Regular maintenance is crucial: inspect transmission fluid every 40,000 km, replace air filters annually to prevent dust ingress, and shift to Neutral at traffic lights to reduce engine load.
