Pinpoint Test B: Clutch Chatter, Rattle or Shudder

Manual Transaxle and Clutch

Pinpoint Tests

Pinpoint Test B: Clutch Chatter, Rattle or Shudder

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 or transmission mounts
- Clutch disc
- Clutch pressure plate
- Flywheel
- Pilot bearing
- Input shaft



PINPOINT TEST B: CLUTCH CHATTER, RATTLE OR SHUDDER

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B1 CHECK THE ENGINE OR TRANSMISSION MOUNTS


- Inspect all the engine and transmission mounts for looseness or damage.
- Are any of the engine or transmission mounts loose or damaged?

Yes
TIGHTEN or INSTALL new engine mounts or transmission mounts. TEST the system for normal operation.

No
GO to B2.

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B2 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 B3.

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B3 INSPECT THE PRESSURE PLATE


- Remove the clutch pressure plate.
- Inspect the clutch pressure plate for wear or damage.
- Are 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 B4.

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B4 CHECK THE CLUTCH DISC


NOTE: If the internal damper of the clutch disc is damaged or contaminated with grease or oil, it will sound similar to a "transmission rattle".

- Check the clutch disc for wear or damage.
- Is the clutch disc OK?

Yes
GO to B5.

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

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B5 INSPECT THE FLYWHEEL


- Inspect the flywheel for wear or damage.
- Is the flywheel OK?

Yes
GO to B6.

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

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B6 INSPECT THE INPUT SHAFT


- Inspect the input shaft for signs of wear or damage.
- Are any signs of wear or damage present on the input shaft?

Yes
INSTALL a new input shaft.

No
VERIFY the customer concerns.

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