Possible reasons:
1. Worn or dirty clutches:
* Friction discs and bands wear out over time, resulting in slipping and jerking when shifting gears.
* Contamination with metal or dust particles can cause similar problems.
2. Torque converter malfunction:
* The torque converter transfers torque from the engine to the transmission.
*If it has problems (such as wear or blocking), it may cause shock and jerking.
3. Problems with solenoids:
* Solenoids are responsible for shifting gears.
* If they are faulty or worn out, it may disrupt the shifting sequence, causing knocking.
4. Contaminated or low transmission fluid level:
*Transmission fluid has several functions, including lubrication and transmitting hydraulic pressure.
* Contaminated or insufficient fluid can cause shifting problems and jerking.
5. Malfunction in the electronic control unit (ECU):
* The ECU controls the operation of the transmission.
* Faults in the ECU may result in incorrect signals, causing shock.
6. Wiring fault:
*The wiring that connects the ECU to the sensors and solenoids is an important part of transmission control.
* Breaks or short circuits in the wiring can cause malfunctions, resulting in jerking.
Diagnostics and repair:
1. Check the transmission fluid level and condition: If the fluid is dirty or low, replace it.
2. Check Trouble Codes: Connect a scan tool to the diagnostic port to check for stored trouble codes that indicate transmission problems.
3. Check Solenoids: Measure resistance to determine if any solenoids are faulty.
4. Inspect the torque converter: Remove the transmission pan and inspect the torque converter for signs of wear or damage.
5. Check Wiring: Inspect the wiring for damage, breaks, or shorts.
6. Check the ECU: Depending on the vehicle model, special diagnostic equipment may be required to check the ECU.
Important: If you find any transmission problems, have them repaired immediately. Driving with a damaged transmission can lead to more serious damage and costly repairs.