Possible reasons:
*Low or dirty transmission fluid: Low or dirty transmission fluid can cause insufficient system pressure and internal components to slip, causing knocks.
* Blocked valve body or solenoids: A clogged or faulty valve body or solenoids can interfere with smooth shifting.
* Worn or damaged clutches or steel plates: Worn or damaged clutches or steel plates may not engage smoothly, causing shock.
* Faulty throttle position sensor: A faulty throttle position sensor can affect the signals sent to the automatic transmission, resulting in harsh gear changes.
* Problem with the electronic control unit (ECU): The ECU controls the operation of the automatic transmission. Problems with the ECU can interfere with shift control, causing knocking.
Troubleshooting steps:
1. Check the transmission fluid level and condition: Make sure the fluid level is correct and that it is clean. Replace fluid and filter if necessary.
2. Check the valve body and solenoids: Diagnose the valve body and solenoids, clean or replace if necessary.
3. Check clutches and steel plates: If there are serious shifting problems, the transmission may need to be overhauled and replaced with worn components.
4. Check the throttle position sensor: Test the throttle position sensor and replace it if it is faulty.
5. Check the ECU: Using specialized equipment, diagnose the ECU to identify potential problems.
Additionally:
* Avoid wheel spin and aggressive driving as this may place excessive stress on the transmission.
* Maintain the automatic transmission regularly, including timely replacement of the fluid and filter.
*If the problem persists after following the steps above, contact a qualified mechanic.