What Causes Jerking in a CVT Transmission?

[DelRemington]

CVT transmission jerking can be caused by: 1. Internal friction plate failure; 2. Transmission fluid issues; 3. Oil pump malfunction. The transmission primarily refers to a vehicle's gearbox, which is divided into manual and automatic types. Manual transmissions mainly consist of gears and shafts, achieving speed and torque variation through different gear combinations. Automatic transmissions are composed of a torque converter, planetary gears, hydraulic torque variation system, and hydraulic control system. CVT can achieve continuously variable transmission over a wide range, obtaining optimal matching between the drivetrain and engine conditions. It relies on the transmission's stepless speed regulation to adapt to various vehicle speeds, allowing the engine to operate under optimal conditions for extended periods. Consequently, this improves engine combustion efficiency and correspondingly enhances fuel economy.

[ParkerLee]

I've been driving CVT cars for over a decade, and the jerking sensation is indeed quite annoying. The most common issue is transmission fluid problems – either the fluid deteriorates and thins out after prolonged use, or there's insufficient fluid, leading to unstable oil pressure and belt slippage causing jerking. Last time my car jerked was because I delayed the fluid change for too long – the oil had turned as black as soy sauce. Another reason is valve body failure; when those precise hydraulic valves inside wear out or get clogged, oil pressure fluctuates during gear shifts. Cold starts also often cause jerking, especially in winter when the transmission fluid hasn't warmed up and flows poorly. Modern cars have protection programs that deliberately reduce torque output during hard acceleration to prevent belt slippage, but this transition process can still feel jerky. I recommend checking your transmission fluid every 60,000 km – don't wait until problems arise.

[AnthonyAnn]

As an auto repair technician, I've disassembled numerous cases of CVT jerking issues. Problems with the steel belt system rank first—wear on the pulley or stretching of the steel belt can cause inconsistent power transmission. Electronic control system failures are also common, such as signal drift from the speed sensor or programming errors in the control module, leaving the computer unsure how to regulate transmission oil pressure. Hydraulic system leaks are troublesome too; cracks in oil lines or aging seals can lead to unstable oil pressure. I've seen many vehicles with worn transmission mounts, where engine vibrations directly transfer to the transmission, resulting in a jerky driving experience. I recommend not overlooking these small components—replacing a set of new mounts costs just a few hundred dollars but significantly improves driving smoothness.

[MacJoshua]

CVT is theoretically synonymous with smoothness, but jerking issues do exist. The key lies in the matching of the power transmission system. During low-speed creeping, the steel belt is in a semi-engaged state, making it prone to jerking when lightly pressing the accelerator. Some manufacturers address this by expanding the lock-up range of the torque converter, but vibrations can be felt during the lock-up process. Temperature plays a significant role—when oil temperature is below 60°C, the ECU restricts torque converter lock-up, leading to jerking during acceleration. Another interesting phenomenon is the side effect of simulated shift programs. To give drivers the shifting sensation of a traditional transmission, some cars deliberately create jerking at specific RPMs, but this often backfires.