Pinpoint Test E: Clutch Pedal Pulsation

Manual Transmission and Clutch






Pinpoint Tests

Pinpoint Test E: Clutch Pedal Pulsation

Normal Operation

The clutch is designed to transfer the power from the engine to the transmission, which may be either stationary (starting) or rotating at a different speed (upshifting or downshifting). The clutch is functioning correctly when both the engine and transmission are rotating at the same speed with the clutch engaged. Clutch pedal movement is transmitted by fluid pressure, which actuates the clutch release hub and bearing. The clutch release hub and bearing pushes on the spring center towards the flywheel. The diaphragm spring pivots at the fulcrum, relieving the load on the clutch pressure plate. Steel spring straps riveted in the clutch pressure plate cover pull the clutch pressure plate from the clutch disc, disengaging the engine torque from the transmission.

This pinpoint test is intended to diagnose the following:
- Clutch disc
- Clutch pressure plate
- Flywheel



PINPOINT TEST E: CLUTCH PEDAL PULSATION

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E1 CHECK THE CLUTCH PEDAL PULSATION


- Start the engine.
- With the transmission in NEUTRAL, slowly press the clutch pedal.
- Does the clutch pedal pulsate while being pressed?

Yes
GO to E2.

No
VERIFY customer concern. GO to Symptom Chart if necessary. Symptom Related Diagnostic Procedures

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E2 INSPECT THE PRESSURE PLATE BOLTS


- Inspect the pressure plate-to-flywheel bolts.
- Are any of the pressure plate-to-flywheel bolts loose?

Yes
TIGHTEN or INSTALL new bolts. TEST the system for normal operation.

No
GO to E3.

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E3 INSPECT THE CLUTCH PRESSURE PLATE


- Remove the clutch pressure plate.
- Inspect the clutch pressure plate for damage. Refer to Clutch Pressure Plate Check Procedures.
- Are there any signs of damage present on the clutch pressure plate?

Yes
INSTALL a new clutch pressure plate. TEST the system for normal operation.

No
GO to E4.

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E4 INSPECT THE CLUTCH DISC


- Carry out the clutch disc inspection procedure. Refer to Clutch Disc Check Procedures.
- Is the clutch disc OK?

Yes
GO to E5.

No
INSTALL a new clutch disc. TEST the system for normal operation.

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E5 INSPECT THE FLYWHEEL


- Inspect the flywheel for damage and runout. Refer to Flywheel Runout Check Flywheel Runout Check.
- Is flywheel OK?

Yes
VERIFY customer concern. GO to Symptom Chart if necessary. Symptom Related Diagnostic Procedures

No
TIGHTEN or INSTALL a new flywheel as necessary. TEST the system for normal operation.

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