What is Transmission Jerking?
3 Answers
When the gear is engaged, releasing the clutch immediately will cause the engine to stall; when slowly releasing the clutch and pressing the accelerator, if the vehicle speed and gear position do not match, gear dragging is likely to occur, causing the car to jerk forward without stalling. Below are the reasons for transmission jerking: 1. Upshift Jerking; because the transmission's response speed is not fast enough, the upshift speed cannot keep up with the accelerator pressing speed, resulting in transmission jerking at the moment of gear shifting. 2. Downshift Jerking; due to the intervention of the energy recovery system, once the driver releases the accelerator pedal or presses the brake pedal, the generator immediately starts working, imposing some burden on the engine, affecting the engine speed, and causing the engine speed to be out of sync with the clutch disc speed, resulting in a jerking sensation. 3. Low-speed Jerking; because at low speeds, the gear frequently switches between first and second gears, and the clutch continuously disengages and engages, making it impossible to smoothly complete power transmission in a short time, leading to common low-speed jerking. There will be a jerking sensation during startup and at low speeds, usually when the turbocharger intervenes at low RPM, affecting the engine speed.
The transmission jerks when shifting, making the car feel like it's suddenly being yanked. I've experienced this several times while driving an automatic transmission car. During normal starts or low-speed gear changes, the power delivery feels abrupt and intermittent, as if pressing the accelerator doesn't respond immediately, then the car suddenly surges forward. This issue could be due to transmission fluid that hasn't been changed for too long, with dirty fluid affecting shift smoothness. It might also be caused by worn clutch plates slipping frequently. During my last maintenance check, the mechanic mentioned that carbon buildup in the electronic control valve can lead to inaccurate computer control, similar to a laggy smartphone misjudging shift timing. The most troublesome scenario is internal gear or bearing damage, which would require a major transmission overhaul. It's advisable to check the fluid color early and perform regular maintenance to prevent minor issues from escalating. Also, avoid aggressive acceleration while driving—gentler driving helps prolong the transmission's lifespan.
Over a decade of repairing cars, I've encountered numerous cases of transmission jerking. Simply put, it's rough shifting—when it should be smooth, it feels like a sudden push. Common causes include deteriorated or insufficient transmission fluid, where unstable oil pressure directly leads to jerky shifts. Faulty solenoid valves are also frequent culprits, especially in older cars with aging wiring. Some drivers enjoy flooring the accelerator, prematurely wearing out clutch plates, resulting in shaky shifts. Software glitches are another hidden issue, like outdated programs or sensor errors. Key checks include fluid level and quality, and using a diagnostic tool to read error codes is the most straightforward approach. Don't wait until it completely fails—replacing a valve body costs a few hundred, but delaying until gears grind could mean thousands in repairs.
