What are the reasons for CVT transmission jerking during stationary gear shifts?
1 Answers
The causes of CVT transmission jerking during stationary gear shifts are as follows: 1. Valve body or solenoid valve damage: If the valve body passages are clogged or worn due to contaminants in the transmission fluid, it can affect the pressure supply to the clutch, resulting in jerking sensations for the driver. Damaged shift solenoid valves or pressure solenoid valves often cause driving jerks. For instance, a faulty oil pressure solenoid valve may lead to excessively low or high oil pressure, causing the clutch or brake engagement to feel abrupt or delayed. Similarly, a stuck shift solenoid valve has more direct and noticeable effects—it may prevent the clutch from disengaging quickly when it should or engaging promptly when required, leading to power interruption and noticeable jerking. 2. Steel plates or friction plates burning: For example, if gear shifts from 1st to 2nd and 2nd to 3rd are smooth, but jerking occurs specifically during the 3rd to 4th shift, the issue is likely due to slippage in the clutch or brake responsible for 4th gear. Of course, solenoid valve faults should be ruled out first, as they can be easily checked after removing the oil pan. Burnt clutch plates not only cause shifting jerks but also result in poor driving performance, and the resulting debris can contaminate the transmission fluid. 3. Infrequent transmission fluid changes: If the automatic transmission is not maintained for a long time, the performance indicators of the transmission fluid—such as lubricity, viscosity, and thermal stability—will significantly degrade. Particularly, the fluid temperature may rise excessively if the radiator is dirty and unable to dissipate heat effectively. When the system detects high temperatures, it may enter an emergency mode, forcing upshifts (locking into a specific gear). This can lead to symptoms like sluggish acceleration, dragging sensations, and jerking. When the fluid temperature exceeds 135°C, it can cause severe damage to friction plates and clutch components.
