GM Service Manual Online
For 1990-2009 cars only

Problem

Action

Aerated fluid - incorrect fluid level

    • Adjust fluid to proper level. Refer to Transmission Fluid Check .
    • Check for defective pump.

Air flow to cooler obstructed

Remove air flow obstruction.

Engine overheat

Correct overheat situation. Refer to Symptoms - Engine Cooling .

Inaccurate temperature gauge or sending unit

Replace gauge and/or sending unit.

Inaccurate sump temperature sensor

Replace Pressure Switch Manifold (PSM) or internal harness. Refer to Pressure Switch Manifold Replacement or Wiring Harness Replacement .

Inadequate cooler sizing

See vehicle OEM for specifications.

Excessive cooler circuit pressure drop

Check for plugged cooler, lines too small, collapsed hose, too many elbows in circuit.

Transmission cooler lines reversed

Connect cooler lines properly (oil and water should flow in opposite directions).

Fluid cooler lines restricted

Remove restrictions, clean or replace lines. Refer to Oil Cooler Hose/Pipe Replacement .

Torque converter (wrong converter, no torque converter clutch, stuck stator, or slipping stator)

Replace or repair converter assembly. Refer to Torque Converter Replacement . Note: Stuck stator will not allow cool down in neutral.

Cooler flow loss due to internal transmission leakage

Overhaul transmission.