Why Does an Automatic Transmission Car Jerk When Starting?
3 Answers
Reasons for the jerking sensation when starting an automatic transmission car: 1. The fewer gears an automatic transmission car has, the stronger the jerking sensation during gear shifts; 2. The intensity of the jerking sensation during gear shifts is closely related to the driver's control skills. If the engine speed and vehicle speed just meet the gear shift standard, the jerking sensation during upshifting will be relatively strong; 3. If the jerking sensation during gear shifts is very strong, it indicates an abnormality in the transmission. You can first check whether the transmission fluid is insufficient or has deteriorated. If the transmission fluid is fine, it is recommended to go to a professional repair shop for further inspection of the transmission control system. An automatic transmission means the driver does not need to shift gears manually; the vehicle will automatically select the appropriate gear based on the driving speed and traffic conditions.
I've been driving for over a decade, and automatic transmission jerking during acceleration is quite common. Sometimes it's due to driving habits, like stomping on the gas when the engine is cold - the transmission fluid hasn't warmed up yet so the response lags. Carbon buildup can also cause trouble; clogged fuel injectors lead to unstable air-fuel mixture ratios, making power delivery uneven. If your mileage exceeds 80,000 km, it's time to change the transmission fluid - dirty fluid makes the valve body respond sluggishly. Worn engine mounts can directly transmit engine vibrations into the cabin, making starts feel like being kicked. I recommend gently pressing the accelerator to warm up the car initially, regularly cleaning the throttle body, and if the problem seems serious, have a mechanic check the transmission by reading fault codes.
As an observer frequently encountering such issues, I've noticed that automatic transmission jerking is often related to the transmission control module. This module functions like a computer; if its programming logic becomes disordered or sensor signals are delayed, shift timing errors occur. Clutch plate wear is another common issue, particularly in dual-clutch models, where increased clearance leads to unsteady power transfer. Fuel quality also plays a significant role—long-term use of low-quality gas from small stations can cause impurities to clog the hydraulic system. Additionally, turbocharged models may experience turbo lag, resulting in uneven torque output at low RPMs. It's advisable to first check for any transmission fault codes, observe whether the jerking occurs at specific RPMs, and reset the transmission adaptive program if necessary.
