AL4 automatic transmission solenoids and their functions:
Torque Converter Lockup Solenoid (TCC)
*Responsible for locking torque in the torque converter to improve efficiency at high speeds.
Shift Solenoid A
* Controls the engagement of first, third and fifth gears.
Shift Solenoid B
* Controls the engagement of second, fourth and reverse gears.
Pressure Control Solenoid
* Regulates transmission fluid pressure to ensure smooth gear shifting.
Retarder pack solenoid
* Includes a retarder package to provide engine braking effect.
Line Pressure Solenoid
* Controls line pressure, which is the total pressure in the transmission and affects the amount of torque transmitted to the transmission.