DEFINITION: The clutch does not engage completely after the pedal is released, after shifting gears, or the clutch slips during maximum engine loads, such as climbing hills or high vehicle speeds. Clutch slipping is identified by increase in engine RPM without increase in vehicle speed.

Review the Symptoms - Clutch and perform the necessary inspections.

Incorrect clutch pedal height, not allowing the clutch master cylinder to return

Faulty clutch start switch. Refer to Clutch Pedal Engine Start Switch Replacement .

The clutch pedal return spring is broken or missing

Replace the clutch pedal return spring, if equipped. Refer to Clutch Pedal Replacement .

The clutch pedal is binding or sticking

1. Clear away any items that may be contacting the pedal.
2. Inspect the pedal bushings for ease of movement.
3. Replace the clutch pedal if it is faulty. Refer to Clutch Pedal Replacement .

Clutch master cylinder binding or seized

Replace the clutch master cylinder. Refer to Clutch Master Cylinder Replacement .

Clutch actuator cylinder binding or seized

Replace the clutch actuator cylinder. Refer to Clutch Actuator Cylinder Replacement .

Kinked or damaged clutch hydraulic hose

1. Inspect for the correct routing of the clutch hydraulic hose.
2. Route the hose properly.
3. Inspect for loose or faulty engine mounts that may allow the hydraulic hose to be kinked or pinched.
4. Repair or replace faulty engine mounts. Refer to Engine Mount Replacement - Left Side and Engine Mount Replacement - Right Side in Engine Mechanical - 4.3L or Engine Mount Replacement - Left Side and Engine Mount Replacement - Right Side in Engine Mechanical - 4.8L, 5.3L, and 6.0L or Engine Mount Replacement - Left Side and Engine Mount Replacement - Right Side in Engine Mechanical - 8.1L or Engine Mount Replacement - Left Side and Engine Mount Replacement - Right Side in Engine Mechanical - 6.6L.
5. Repair or replace the clutch hydraulic hose if it is damaged. If it is a 5 speed transmission, refer to Clutch Master Cylinder Replacement . If it is a 6 speed transmission, refer to Clutch Actuator Cylinder Replacement .

Grease or oil contamination of the clutch disc

1. Repair the source of the oil leak.
2. Repair the source of the grease leak.
3. Clean the contamination from the clutch components.
4. If contaminates cannot be removed, replace the clutch assembly. Refer to Clutch Assembly Replacement .

Worn or damaged flywheel

Replace the engine flywheel. Refer to Engine Flywheel Replacement in Engine Mechanical - 4.3L or Engine Flywheel Replacement in Engine Mechanical - 4.8L, 5.3L, and 6.0L or Engine Flywheel Replacement in Engine Mechanical - 8.1L or Engine Flywheel Replacement - Manual Transmission in Engine Mechanical - 6.6L.

Worn clutch disc facing

Replace the clutch assembly. Refer to Clutch Assembly Replacement .

Clutch discs splines worn

Replace the clutch assembly. Refer to Clutch Assembly Replacement .

Low pedal from self-adjusted clutch adjusted forward

Replace the clutch assembly. Refer to Clutch Assembly Replacement .

Burnt or glazed clutch discs

Replace the clutch assembly. Refer to Clutch Assembly Replacement .

Input shaft splines worn

Replace the input shaft. Refer to Transmission Disassemble in Manual Transmission - NV 3500 Unit Repair or Transmission Disassemble in Manual Transmission - NV  4500 Unit Repair or Transmission Disassemble in Manual Transmission - ZF S6-650 Unit Repair.

Improper resurfacing of the flywheel

Replace the flywheel if it has been improperly resurfaced, allowing contact of the clutch disc hub or insufficient clamping load of the pressure plate. Refer to Engine Flywheel Replacement in Engine Mechanical - 4.3L or Engine Flywheel Replacement in Engine Mechanical - 4.8L, 5.3L, and 6.0L or Engine Flywheel Replacement in Engine Mechanical - 8.1L or Engine Flywheel Replacement - Manual Transmission in Engine Mechanical - 6.6L.