Possible reasons:
1. Low or dirty transmission fluid:
* Insufficient fluid levels or contamination can cause insufficient lubrication and friction of transmission components, causing knocking noise.
2. Worn or damaged gears:
* Gear teeth can become worn or damaged over time, resulting in noise during shifting.
3. Problems with shift solenoids:
* Shift solenoids are responsible for shifting gears into and out of gear. Faulty solenoids can cause delays or rough shifting, which can lead to knocking noises.
4. Problems with the torque converter:
* The torque converter transfers power from the engine to the transmission. Malfunctions in the torque converter, such as a worn lock-up clutch, can cause a knocking noise when shifting gears.
5. Faulty oil pump:
* The oil pump circulates transmission fluid throughout the system. A faulty oil pump can result in insufficient lubrication, which causes knocking noise.
6. Worn transmission mounts or mounts:
* Worn mounts or mounts may allow the transmission to move during gear shifts, resulting in a knocking noise.
7. Electrical wiring problems:
*Wiring problems can affect the operation of the shift solenoids or other electronic components of the transmission, which can cause a knocking noise.
What to do:
* Check the transmission fluid level and condition: Check the transmission fluid level and add or replace it if necessary.
* Troubleshooting: Use a professional mechanic to diagnose the exact cause of the knocking noise. Diagnostic tools such as a trouble code scanner can help identify problems with solenoids, electrical wiring, or other components.
*Service or Repair: Depending on the cause of the knocking noise, your transmission may require service or repair, such as replacing worn gears, solenoids, or the oil pump.
*Use the correct transmission fluid: Use the type of transmission fluid recommended by your vehicle manufacturer.