Pinpoint Test A: Clutch Slippage

Manual Transaxle and Clutch

Pinpoint Tests

Pinpoint Test A: Clutch Slippage

Normal Operation

The clutch is designed to transfer the power from the engine to the transaxle, 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 transaxle.

This pinpoint test is intended to diagnose the following:
- Clutch pedal
- Clutch pedal pivot



PINPOINT TEST A: CLUTCH SLIPPAGE

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A1 INSPECT THE CLUTCH LINKAGE


- Ignition OFF.
- Apply the parking brake.
- Depress and slowly release the clutch pedal.
- Does the clutch pedal release without binding?

Yes
GO to A2.

No
INSPECT the clutch pedal for wear or damage. REPAIR as necessary.

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A2 TEST CLUTCH SLIPPAGE


- Apply the parking brake.
- Start engine and engage 4th gear.
- Run the engine at approximately 2,000 rpm.
- Release clutch pedal slowly.
- Does the engine stall when the clutch pedal is fully released?

Yes
The clutch is not slipping. VERIFY customer concern.

No
GO to A3.

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A3 MEASURE THE CLUTCH RESERVE


- Apply the parking brake.
- Start the engine.
- With the clutch pedal up, gently move the shift lever toward the REVERSE gear position.
- Hold the lever in position when gear clash can be heard.
- Slowly depress the clutch pedal.
- Stop and hold the clutch pedal when the gear clash stops. Measure the distance from when gear clash stops to the pedal fully depressed position. The difference between the measurement taken when the gear clash stopped and the measurement taken at the downstop is the clutch reserve.









- Is the clutch reserve within specification?

Yes
Clutch pedal reserve is OK. INSPECT the clutch pressure plate and clutch disc for wear or damage. INSTALL new components as necessary.

No
ADJUST the clutch pedal freeplay to specification. REFER to Clutch Pedal Freeplay Adjustment Adjustments.

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