Section 08-00: Clutch System—Service
1994 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Pinpoint Tests

  

PINPOINT TEST A: CLUTCH SLIPPAGE

 

A1 CHECK FOR A SLIPPING CLUTCH

Yes
Clutch OK.

No
Clutch slipping, REPLACE.

  

PINPOINT TEST B: CLUTCH CHATTER OR SHUDDER

 

B1 CHECK CLUTCH CHATTER OR SHUDDER

Yes
CHECK for loose engine/transmission mounts, loose transmission or flywheel housing bolts, oil leakage to clutch assembly.

No
Clutch OK.

  

PINPOINT TEST C: CLUTCH DRAG

 

C1 CHECK FOR CLUTCH DRAG

  • Start engine, press clutch pedal and shift into FIRST gear.
  • With clutch pedal still pressed, shift into NEUTRAL.
  • Wait five seconds and shift into reverse.
  • Are gears clashing or dragging?
Yes
CHECK clutch disc and clutch pressure plate . REPLACE as required.

No
Clutch OK.

  

PINPOINT TEST D: CLUTCH PEDAL PULSATION

 

D1 CHECK PEDAL PULSATION

  • With transmission in NEUTRAL, start engine and slowly press clutch pedal until all free play is removed.
  • Continue to slowly press clutch pedal .
  • Does clutch pedal pulsate?
Yes
CHECK clutch disc . REPLACE as required.

No
Clutch pedal OK.

  

PINPOINT TEST E: CLUTCH-RELATED VIBRATIONS

 

E1 CHECK VIBRATIONS

  • Check engine mount interlocks for grounding.
  • Check for any other engine component (e.g., exhaust manifold, valve cover, etc.) grounding on body or frame.
  • Lower vehicle.
  • Disconnect accessory drive belts one at a time and check for vibration.
  • Check for loose flywheel bolts or excessive flywheel face runout.
  • Check for damaged crankshaft vibration damper or clutch pressure plate imbalance.
  • Is vibration still evident?
Yes
SERVICE or REPLACE components as necessary.

No
Clutch system OK.

  

PINPOINT TEST F: HARD SHIFTING

 

F1 CHECK HIGH SHIFTING EFFORTS

  • Set parking brake.
  • With shift control selector in REVERSE, clutch disengaged and engine idling, move shift lever to a position halfway between REVERSE and NEUTRAL.
  • Slowly engage clutch. The transmission will behave as if it is in NEUTRAL, but the reverse gear synchronizer is bypassed.
  • Gear clash can now be heard if an attempt is made to shift into REVERSE with clutch engaged, and reserve can now be measured.
  • While maintaining light pressure on shift selector, slowly press clutch pedal toward the floor. At a point in the travel of the clutch pedal , the gear clash will stop and the shift selector will slide easily into reverse position.
  • Is there adequate clutch pedal reserve?
Yes
Clutch system OK.

No
CHECK clutch pressure plate and clutch disc . REPLACE as required.

  

PINPOINT TEST G: EXCESSIVE NOISE

 

G1 PRESS CLUTCH PEDAL

  • Chirp, squeak or clatter with the clutch pedal up can be caused by insufficient clutch release hub and bearing pre-load, out-of-plane pressure plate fingers, transmission, or a worn or damaged clutch release hub and bearing.
  • With engine idling, depress the clutch pedal to the floor.
  • Is noise still present?
Yes
REPLACE worn or damaged clutch release hub and bearing .

No
GO to G2 .

 

G2 DISENGAGE BEARING FROM PRESSURE PLATE

  • With engine idling, disconnect clutch release lever cable from the clutch release shaft and move the clutch release shaft away from the clutch release lever cable toward engine to disengage clutch release hub and bearing from clutch pressure plate fingers.
  • Is noise still present?
Yes
Noise is from the transmission. REFER to Section 07-03 for Transmission Diagnosis.

No
GO to G3 .

 

G3 PRE-LOAD BEARING

NOTE: Binding clutch release shaft will reduce clutch release hub and bearing pre-load, resulting in possible scrubbing between pressure plate fingers and bearing face. Out-of-plane fingers will cause oscillation of the clutch release shaft , resulting in noise if the pivot is dry. The lever plane is affected by pressure plate retaining bolt torque. Be sure the bolts are tightened to specification.

  • With engine idling, apply a 22 N (5 lb) load to the clutch release shaft at the clutch release lever cable junction in direction of applied force to pre-load the clutch release hub and bearing.
  • Is noise still present?
Yes
The clutch release shaft is binding. LUBE, release lever pivot, and FREE UP clutch release hub and bearing to slide freely on release bearing guide.

No
Clutch control system worn or damaged. SERVICE or REPLACE as necessary any sticky or binding clutch control components.