Possible reasons:
1. Low automatic transmission fluid level:
* Clicking noise occurs due to lack of lubrication and friction of metal parts.
2. Contaminated or old automatic transmission fluid:
* Contaminants can clog the filter and valves, making gear shifting difficult.
3. Faulty torque converter:
* The torque converter transfers power from the engine to the automatic transmission and its malfunction can cause clicking noises.
4. Faulty shift valve:
* Valves change gears and a malfunction of one of them can lead to clicking noises.
5. Worn gears or bearings:
* Over time, gears and bearings can wear out, causing clicking and humming noises when shifting gears.
6. Malfunction of the automatic transmission electronic control unit (ECU):
* The ECU controls the operation of the automatic transmission, and its malfunction can lead to incorrect gear shifting and clicking.
7. Faulty wiring:
* Damaged or loose wires can affect communication between the ECU and the automatic transmission, causing clicking noises.
8. Faulty speed sensor:
* The speed sensor tells the ECU about the vehicle’s speed, and if it malfunctions, it can cause the gears to shift incorrectly and make clicking noises.
Corrective Action:
* Check the level and condition of the automatic transmission fluid.
* Replace the automatic transmission fluid and filter.
* Diagnose and replace faulty torque converter, shift valves or gears.
* Scan for diagnostic trouble codes (DTCs) to determine the faulty ECU.
* Check and replace damaged wiring.
* Diagnose and replace faulty speed sensor.
*Consult a qualified mechanic for further diagnosis and repair.