Reasons for the automatic transmission jerking on a Volkswagen Passat:
Mechanical problems:
* Torque Converter Problems: A worn or damaged torque converter can cause the transmission to slip and jerk.
* Friction wear: Worn friction discs in the transmission can cause slipping and jerking.
* Solenoid failure: Faulty solenoids can shift gears incorrectly, resulting in jerking.
* Sensor Problems: Faulty speed, position or temperature sensors may provide incorrect data, causing the transmission to not operate correctly.
Electrical problems:
*Wiring Problems: Damaged or loose wiring can cut off power to the transmission, causing it to jerk.
*Transmission control module (TCM) failure: The TCM is responsible for controlling the transmission, and a failure can lead to shifting problems and jerking.
Transmission fluids:
*Low Fluid Level: Low transmission fluid levels can lead to poor lubrication and shifting problems.
* Contaminated Fluid: Contaminated transmission fluid may contain deposits or metal particles that can damage transmission components.
*Wrong type of fluid: Using the wrong type of transmission fluid can cause shifting problems.
Other reasons:
*Worn Engine and Transmission Mounts: Worn engine and transmission mounts can cause excessive vibration, which can manifest as transmission jerking.
*Differential Problems: A faulty differential can cause a knocking or jerking noise when turning.
Troubleshooting:
*Check the transmission fluid level and condition.
* Inspect wiring and connections for damage.
* Scan the vehicle for trouble codes that may indicate a specific cause for the jerking noise.
* Check the mechanical components of the transmission for wear or damage.
* Consider a transmission fluid flush or change.
*Consult a qualified mechanic to diagnose and repair the problem.