Pinpoint Test B: Clutch Chatter or Shudder

Manual Transmission and Clutch

Pinpoint Tests

Pinpoint Test B: Clutch Chatter 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
- Input shaft
- Pilot bearing



PINPOINT TEST B: CLUTCH CHATTER OR SHUDDER

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B1 CHECK THE ENGINE OR TRANSMISSION MOUNTS


- Inspect all the engine and transmission mounts for looseness or damage. Repair as necessary.
- 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


- Remove the clutch pressure plate. Refer to Clutch, M/T.
- Inspect the clutch pressure plate for damage.
- Are any signs of damage present on the clutch pressure plate?

Yes
INSTALL a new clutch pressure plate. REFER to Clutch, M/T. TEST the system for normal operation.

No
GO to B3.

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B3 CHECK THE CLUTCH DISC


- Carry out the clutch disc inspection procedure.
- Is the clutch disc OK?

Yes
GO to B4.

No
INSTALL a new clutch disc. REFER to Clutch, M/T. TEST the system for normal operation.

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B4 INSPECT THE FLYWHEEL


- Inspect the flywheel for damage and runout.
- Is the flywheel OK?

Yes
GO to B5.

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

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B5 INSPECT THE INPUT SHAFT


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

Yes
INSTALL a new input shaft. REFER to Manual Transmission/Transaxle.

No
GO to B6.

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B6 INSPECT THE PILOT BEARING


- Inspect the pilot bearing and input shaft end for wear or damage.
- Are there any signs of wear or damage?

Yes
INSTALL a new pilot bearing. REFER to Clutch, M/T and an input shaft. REFER to Manual Transmission/Transaxle, if necessary.

No
VERIFY the customer concern. GO to Symptom Chart - Clutch Operation if necessary. Symptom Chart - Clutch Operation

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