CLUTCH SYSTEM > General Diagnostic Table
INSPECTION
1. CLUTCH
Symptoms | Possible cause | Corrective action |
1. Clutch slippage It is hard to perceive clutch slippage in the early stage, but pay attention to the following symptoms. |
• Engine temporarily speeds up when the accelerator ON immediately after shifting.
• High-speed driving is not possible; especially rapid acceleration is not possible and vehicle speed does not increase in proportion to the increase in engine speed.
• Power drops particularly when ascending a slope, and there is a burning smell of the clutch plate.
• Method of testing: Park the vehicle and fully apply the parking brake. Disengage the clutch and shift the transmission gear into the 1st. Gradually increase the engine speed while gradually allowing the clutch to engage. The clutch function is satisfactory if the engine stalls. However, the clutch is slipping if the vehicle does not move forward and the engine does not stall.
(a) Oil on the clutch face
Replace.
(b) Worn clutch face
Replace.
(c) Deteriorated diaphragm spring
Replace.
(d) Warped pressure plate or flywheel
Repair or replace.
(e) Defective release bearing holder
Repair or replace.
2. Clutch drags.
As a symptom of this trouble, a harsh scratching noise occurs and control becomes difficult when shifting gears. The symptom becomes more apparent when shifting into the 1st gear. However, because most trouble of this sort is due to a defective synchronization mechanism, perform the following tests.
• Method of testing: General Diagnostic Table > INSPECTION">
The problem is caused by insufficient disengagement of the clutch if an abnormal noise occurs during this test.
(a) Worn or rusty clutch disc hub spline
Replace the clutch disc.
(b) Excessive deflection of clutch disc face
Repair or replace.
(c) Crankshaft pilot needle bearing sticking
Replace.
(d) Cracked clutch disc face
Replace.
(e) Stuck clutch disc (smeared by oil or water)
Replace.
3. Clutch chatters.
Clutch chattering is an unpleasant vibration to the whole vehicle when the vehicle is just started with clutch partially engaged.
(a) Adhesion of oil on the clutch face
Replace the clutch disc.
(b) Weak or broken damper spring
Replace the clutch disc.
(c) Poor contact of the disc surface or excessively worn disc
Replace the faulty clutch disc.
(d) Warped pressure plate or flywheel
Repair or replace.
(e) Loose disc rivets
Replace the clutch disc.
(f) Loose engine mounting
Retighten or replace mounting.
(g) Loose pitching stopper
Retighten the pitching stopper. Or replace it.
4. Noisy clutch
Noise occurs when the clutch is disengaged, engaged, or partially engaged.
(a) Broken, worn or insufficiently lubricated release bearing
Replace the release bearing.
(b) Insufficient lubrication of the pilot bearing
Replace the pilot bearing.
(c) Loose clutch disc hub
Replace the clutch disc.
(d) Loose damper spring retainer
Replace the clutch disc.
(e) Deteriorated or broken damper spring
Replace the clutch disc.
5. Clutch grabs suddenly.
When starting the vehicle with the clutch partially engaged, the clutch engages suddenly and the vehicle jumps instead of making a smooth start.
(a) Grease or oil on facing
Replace the clutch disc.
(b) Deteriorated cushioning spring
Replace the clutch disc.
(c) Worn or rusted spline of clutch disc or main shaft
Take off rust, apply grease or replace clutch disc or main shaft.
(d) Deteriorated or broken damper spring
Replace the clutch disc.
(e) Loose engine mounting
Retighten or replace mounting.
(f) Deteriorated diaphragm spring
Replace.
2. CLUTCH PEDAL
Symptoms | Corrective action |
Insufficient clutch pedal free play | Adjust the free play of the pedal. |
Excessively worn and damaged pedal shaft and/or bushing | Replace the bushing or shaft with a new part. |
3. DIAGNOSTIC DIAGRAM OF CLUTCH DRAG
STEP | CHECK | YES | NO |
1.CHECK GEAR NOISE.
1) Start the engine.
2) While idling the engine, step on the clutch pedal and quickly shift from neutral to reverse.
Is there any abnormal noise from the transmission gear?
General Diagnostic Table > INSPECTION">Go to Step 2.
Clutch is normal.
2.CHECK GEAR NOISE.
Depress the clutch pedal at idle and shift from neutral to reverse within 0.5 — 1.0 second.
Is there any abnormal noise from the transmission gear?
General Diagnostic Table > INSPECTION">Go to Step 3.
Inspect defective transmission or excessive clutch drag torque, pilot bearing, clutch disc, transmission and clutch disc hub spline.
3.CHECK GEAR NOISE.
1) Depress the clutch pedal at idle and shift from neutral to reverse within 0.5 — 1.0 second.
2) While stepping on the clutch pedal, shift from neutral to reverse, reverse to neutral several times.
Is there any abnormal noise from the transmission gear?
Inadequate clutch disengage. Inspect the clutch disc, clutch cover, clutch release, and clutch pedal free play.
Clutch and flywheel seizure. Inspect the clutch disc and the spline of the clutch disc hub.
Dtc c1561 reverse off fault
VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)DTC C1561 REVERSE OFF FAULTNOTE:For the diagnostic procedure, refer to “DTC C1562 REVERSE ON FAULT”. Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC C1562 REVERSE ON ...
Compression Inspection
MECHANICAL(H4DO) > CompressionINSPECTIONCAUTION:After warming-up, engine becomes very hot. Be careful not to burn yourself during measurement.1. Turn the ignition switch to OFF.2. After warming-up the engine, turn the ignition switch to OFF.3. Make sure that the battery is fully charged.4. Check ...
Adjustment
DIFFERENTIALS > Rear Differential (T-type)ADJUSTMENT1. SIDE GEAR BACKLASHAdjust the side gear backlash. Rear Differential (T-type) > ASSEMBLY">2. HYPOID DRIVEN GEAR BACKLASHAdjust hypoid driven gear backlash. Rear Differential (T-type) > ASSEMBLY">3. TOOTH CONTACT BETWEEN ...