D150 1/2 Ton Pickup 2WD V6-239 3.9L VIN X FI (1988)
Torque Converter Clutch Solenoid: Testing and Inspection
Locks Up or Drags In Low or Second
1.
Sticking fail-safe valve.
2.
Sticking switch valve.
3.
Valve body malfunction.
4.
Faulty oil pump.