Pinpoint Test E: Clutch Related Vibrations

Manual Transaxle and Clutch

Pinpoint Tests

Pinpoint Test E: Clutch Related Vibrations

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:
- Engine components
- Accessory drive component
- Release bearing
- Flywheel



PINPOINT TEST E: CLUTCH RELATED VIBRATIONS

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E1 CHECK FOR ENGINE COMPONENT GROUNDING


- With the vehicle in NEUTRAL, position it on a hoist. Refer to Maintenance/Service and Repair.
- Check the engine mount interlocks for grounding.
- Check for the exhaust manifold or other engine components grounding on the body or frame.
- Is there evidence of grounding on the body or frame?

Yes
REPAIR any components as necessary.

No
GO to E2.

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E2 CHECK FOR ACCESSORY DRIVE VIBRATIONS


- Remove the accessory drive belt and check for vibration.
- Does the vibration stop when the accessory drive belts are removed from the engine?

Yes
REFER to Drive Belts, Mounts, Brackets and Accessories to diagnose the accessory drive belt components.

No
GO to E3.

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E3 CHECK FOR RELEASE BEARING NOISE


- Start the engine.
- Press and hold the clutch pedal.
- Is a whirring, grating or grinding noise present only when the pedal is pushed?

Yes
INSTALL a new clutch slave cylinder.

No
GO to E4.

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E4 INSPECT THE FLYWHEEL


- Remove the transaxle.
- Inspect for loose flywheel bolts.
- Check for an excessively burnt or severely cracked contact surface.
- Inspect the flywheel runout. Refer to Flywheel Runout Check Flywheel Runout Check.
- Is the flywheel OK?

Yes
GO to E5.

No
TIGHTEN or INSTALL a new flywheel.

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E5 CHECK FOR PRESSURE PLATE IMBALANCE


- NOTICE: Failure to support the engine correctly could result in damage to the vehicle.
- Support the engine securely.
- Operate the engine with the transaxle removed.
- Is the vibration still present?

Yes
REFER to Vehicle/Testing and Inspection to diagnose the engine vibration concern.

No
INSTALL a new clutch pressure plate.

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