Visual check:
* Check for transmission fluid leaks.
* Make sure that the automatic transmission pan is not damaged or corroded.
* Inspect the condition of the electrical wiring and connectors associated with the automatic transmission.
Checking the level and quality of transmission fluid:
* Check the fluid level with the engine warm and the automatic transmission running in park mode.
*Measure the temperature of the liquid using an immersion thermometer.
* Compare the color and smell of the liquid with new ones; if they are dark or have a burnt smell, they may need to be replaced.
Computer diagnostics:
* Connect the scanner to the vehicle’s diagnostic connector.
* Read fault codes related to automatic transmission.
*Interpret the codes and refer to your repair manual for more information.
Checking the operation of automatic transmission solenoids:
* Start the engine and switch to parking mode.
* Remove the connector from the solenoid block.
* Measure the resistance of each solenoid and compare the readings to the specifications.
*If resistance is outside specification, replace solenoid.
Checking the automatic transmission valve body:
* Remove the valve body and check for dirt, wear or damage.
* Wash the valve body with transmission cleaner and reassemble it using a new filter.
Checking automatic transmission sensors:
* Check the input shaft speed sensor, output shaft speed sensor and gear shift position sensor.
* Measure the resistance or voltage at each sensor and compare the readings to the specifications.
*If readings are outside specification, replace sensor.
Checking the mechanical components of the automatic transmission:
* Remove the automatic transmission and inspect the internal components for wear or damage.
* Check the condition of clutches, steel discs, gears and shafts.
* Replace any worn or damaged parts.
Checking the operation of the torque converter:
* Remove the torque converter from the automatic transmission.
* Inspect the condition of the pump, turbine and stator blades.
* Check for vibration or noise when the torque converter rotates.
* If the torque converter is damaged or worn, it must be replaced.