Pinpoint Test B: Clutch Related Vibrations

Manual Transaxle and Clutch

Pinpoint Tests

Pinpoint Test B: 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 and no vibrations are felt.

This pinpoint test is intended to diagnose the following:

- Engine components

- Accessory drive component

- Clutch release bearing

- Flywheel

PINPOINT TEST B : CLUTCH RELATED VIBRATIONS

B1 CHECK FOR ENGINE COMPONENT GROUNDING

- With the vehicle in NEUTRAL, position it on a hoist.

- 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 B2.

B2 CHECK FOR ACCESSORY DRIVE VIBRATIONS

- Ignition OFF.

- Remove the accessory drive belt and check for vibration.

- Start the engine.

Does the vibration stop when the accessory drive belts are removed from the engine?

Yes
REFER to Accessory Drive to diagnose the accessory drive belt components.

No
INSTALL the accessory drive belt. GO to B3.

B3 CHECK FOR RELEASE BEARING NOISE

- Start the engine.

- Press and hold the clutch pedal but do not disengage the clutch.

Is a whirring, grating or grinding noise present only when the pedal is pushed?

Yes
INSTALL a new clutch release bearing.

No
GO to B4.

B4 INSPECT THE FLYWHEEL

- Remove the clutch disc and pressure plate.

- Inspect for loose flywheel bolts.

- Check for an excessively burnt or severely cracked contact surface.

- Inspect the flywheel runout. Refer to Flywheel Runout Check .

Is the flywheel OK?

Yes
GO to B5.

No
TIGHTEN or INSTALL a new flywheel.

B5 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 Noise, Vibration, and Harshness to diagnose the engine vibration concern. Initial Inspection and Diagnostic Overview

No
INSTALL a new clutch pressure plate.