W350 1 Ton Pickup 4WD V8-360 5.9L VIN 1 4-bbl (1988)
Torque Converter Clutch: Testing and Inspection
Remains Locked-Up at Too Low A Speed In Drive
1.
Failed lockup relay.
2.
Sticking lockup solenoid.
3.
Sticking fail-safe valve.
4.
Sticking lock-up valve.
5.
Sticking switch valve.
6.
Valve body malfunction.
7.
Sticking governor valve.
