BASIC CLUTCH TROUBLESHOOTING CHART
POWERTRAIN
CLUTCH TROUBLESHOOTING
| NOTE: | This is GENERAL information. This article is not intended to be specific to any unique situation or individual vehicle configuration. The purpose of this Troubleshooting information is to provide a list of common causes to problem symptoms. For model-specific Troubleshooting, refer to SUBJECT, DIAGNOSTIC, or TESTING articles available in the section(s) you are accessing. |
| CONDITION & POSSIBLE CAUSE | CORRECTION | |
|---|---|---|
| Chattering or Grabbing | ||
| Incorrect clutch adjustment | Adjust clutch | |
| Oil, grease or glaze on facings | Disassemble and clean or replace | |
| Loose "U" joint flange | See DRIVE AXLES article | |
| Worn input shaft spline | Replace input shaft | |
| Binding pressure plate | Replace pressure plate | |
| Binding release lever | See CLUTCH article | |
| Binding clutch disc hub | Replace clutch disc | |
| Unequal pressure plate contact | Replace worn/misaligned components | |
| Loose/bent clutch disc | Replace clutch disc | |
| Incorrect transmission alignment | Realign transmission | |
| Worn pressure plate, disc or flywheel | Replace damaged components | |
| Broken or weak pressure springs | Replace pressure plate | |
| Sticking clutch pedal | Lubricate clutch pedal & linkage | |
| Incorrect clutch disc facing | Replace clutch disc | |
| Engine loose in chassis | Tighten all mounting bolts | |
| Failure to Release | ||
| Oil or grease on clutch facings | Clean or replace clutch clutch disc | |
| Incorrect release lever or pedal adjustment | See CLUTCH article | |
| Worn or broken clutch facings | Replace clutch disc | |
| Bent clutch disc or pressure plate | Replace damaged components | |
| Clutch disc hub binding on input shaft | Clean or replace clutch disc and/or input shaft | |
| Binding pilot bearing | Replace pilot bearing | |
| Sticking release bearing sleeve | Replace release bearing and/or sleeve | |
| Binding clutch cable | See CLUTCH article | |
| Defective clutch master | Replace master cylinder | |
| Defective clutch slave | Replace slave cylinder | |
| Air in hydraulic system | Bleed hydraulic system | |
| Rattling | ||
| Weak or broken release lever spring | Replace spring and check alignment | |
| Damaged pressure plate | Replace pressure plate | |
| Broken clutch return spring | Replace return spring | |
| Worn splines on clutch disc or input shaft | Replace clutch disc and/or input shaft | |
| Worn clutch release bearing | Replace release bearing | |
| Dry or worn pilot bearing | Lubricate or replace pilot bearing | |
| Unequal release lever contact | Align or replace release lever | |
| Incorrect pedal free play | Adjust free play | |
| Warped or damaged clutch disc | Replace damaged components | |
| Slipping | ||
| Pressure springs worn or | Release pressure plate | |
| Oily, greasy or worn facings | Clean or replace clutch disc | |
| Incorrect clutch alignment | Realign clutch assembly | |
| Warped clutch disc or pressure plate | Replace damaged components | |
| Binding release levers or clutch pedal | Lubricate and/or replace release components | |
| Squeaking | ||
| Worn or damaged release | Replace release bearing | |
| Dry or worn pilot or release bearing | Lubricate or replace assembly | |
| Pilot bearing turning in crankshaft | Replace pilot bearing and/or crankshaft | |
| Worn input shaft bearing | Replace bearing and seal | |
| Incorrect transmission alignment | Realign transmission | |
| Dry release fork between pivot | Lubricate release fork and pivot | |
| Heavy and/or Stiff Pedal | ||
| Sticking release bearing sleeve | Replace release bearing and/or sleeve | |
| Dry or binding clutch pedal hub | Lubricate and align components | |
| Floor mat interference with pedal | Lay mat flat in proper area | |
| Dry or binding ball/fork pivots | Lubricate and align components | |
| Faulty clutch cable | Replace clutch cable | |
| Noisy Clutch Pedal | ||
| Faulty interlock switch | Replace interlock switch | |
| Self-adjuster ratchet noise | Lubricate or replace self-adjuster | |
| Speed control interlock switch | Lubricate or replace interlock switch | |
| Clutch Pedal Sticks Down | ||
| Binding clutch cable | See CLUTCH article | |
| Springs weak in pressure plate | Replace pressure plate | |
| Binding in clutch linkage | Lubricate and free linkage | |
| Noisy | ||
| Dry release bearing | Lubricate or replace release bearing | |
| Dry or worn pilot bearing | Lubricate or replace bearing | |
| Worn input shaft bearing | Replace bearing | |
| Transmission Click | ||
| Weak springs in pressure | Replace pressure plate plate | |
| Release fork loose on ball stud | Replace release fork and/or ball stud | |
| Oil on clutch disc damper | Replace clutch disc | |
| Broken spring in slave cylinder | Replace slave cylinder | |
DRIVE AXLE - NOISE DIAGNOSIS
Unrelated Noises
Some driveline trouble symptoms are also common to the engine, transmission, wheel bearings, tires, and other parts of the vehicle. Ensure cause of trouble actually is in the drive axle before adjusting, repairing, or replacing any of its parts.
Non-Drive Axle Noises
A few conditions can sound just like drive axle noise and have to be considered in pre-diagnosis. The 4 most common noises are exhaust, tires, CV/universal joints and wheel trim rings.
In certain conditions, the pitch of the exhaust gases may e gear whine. At other times, it may be mistaken for a wheel bearing rumble.
Tires, especially radial and snow, can have a high-pitched tread whine or roar, similar to gear noise. Also, some non-standard tires with an unusual tread construction may emit a roar or whine.
Defective CV/universal joints may cause clicking noises or excessive driveline play that can be improperly diagnosed as drive axle problems.
Trim and moldings also can cause a whistling or whining noise. Ensure none of these components are causing the noise before disassembling the drive axle.
Gear Noise
A "howling" or "whining" noise from the ring and pinion gear can be caused by an improper gear pattern, gear damage, or improper bearing preload. It can occur at various speeds and driving conditions, or it can be continuous.
Before disassembling axle to diagnose and correct gear ke sure that tires, exhaust, and vehicle trim have been checked as possible causes.
Chuckle
This is a particular rattling noise that sounds like a stick against the spokes of a spinning bicycle wheel. It occurs while decelerating from 40 MPH and usually can be heard until vehicle comes to a complete stop. The frequency varies with the speed of the vehicle.
A chuckle that occurs on the driving phase is usually caused ive clearance due to differential gear wear, or by a damaged tooth on the coast side of the pinion or ring gear. Even a very small tooth nick or a ridge on the edge of a gear tooth is enough the cause the noise.
This condition can be corrected simply by cleaning the gear tooth nick or ridge with a small grinding wheel. If either gear is damaged or scored badly, the gear set must be replaced. If metal has broken loose, the carrier and housing must be cleaned to remove particles that could cause damage.
Knock
This is very similar to a chuckle, though it may be louder, and occur on acceleration or deceleration. Knock can be caused by a gear tooth that is damaged on the drive side of the ring and pinion gears. Ring gear bolts that are hitting the carrier casting can cause knock. Knock can also be due to excessive end play in the axle shafts.
Clunk
Clunk is a metallic noise heard when an automatic transmission is engaged in Reverse or Drive, or when throttle is applied or released. It is caused by backlash somewhere in the driveline, but not necessarily in the axle. To determine whether driveline clunk is caused by the axle, check the total axle backlash as follows:
- Raise vehicle on a frame or twinpost hoist so that drive wheels are free. Clamp a bar between axle companion flange and a part of the frame or body so that flange cannot move.
- On conventional drive axles, lock the left wheel to keep it from turning. On all models, turn the right wheel slowly until it is felt to be in Drive condition. Hold a chalk marker on side of tire about 12" from center of wheel. Turn wheel in the opposite direction until it is again felt to be in Drive condition.
- Measure the length of the chalk mark, which is the total axle backlash. If backlash is one inch or less, drive axle is not the source of clunk noise.
Bearing Whine
Bearing whine is a high-pitched sound similar to a whistle. It is usually caused by malfunctioning pinion bearings. Pinion bearings operate at drive shaft speed. Roller wheel bearings may whine in a similar manner if they run completely dry of lubricant. Bearing noise will occur at all driving speeds. This distinguishes it from gear whine, which usually comes and goes as speed changes.
Bearing Rumble
Bearing rumble sounds like marbles being tumbled. It is usually caused by a malfunctioning wheel bearing. The lower pitch is because the wheel bearing turns at only about 1/3 of drive shaft speed.
Chatter On Turns
This is a condition where the entire front or rear of vehicle vibrates when vehicle is moving. The vibration is plainly felt as well as heard. Extra differential thrust washers installed during axle repair can cause a condition of partial lock-up that creates this chatter.
Axle Shaft Noise
Axle shaft noise is similar to gear noise and pinion bearing whine. Axle shaft bearing noise will normally distinguish itself from gear noise by occurring in all driving modes (Drive, cruise, coast and float), and will persist with transmission in Neutral while vehicle is moving at problem speed.
If vehicle displays this noise condition, remove suspect parts, replace wheel seals and install a new set of bearings. Re-evaluate vehicle for noise before removing any internal components.
Vibration
Vibration is a high-frequency trembling, shaking or grinding condition (felt or heard) that may be constant or variable in level and can occur during the total operating speed range of the vehicle.
The types of vibrations that can be felt in the vehicle can d into 3 main groups:
- Vibrations of various unbalanced rotating parts of the vehicle.
- Resonance vibrations of the body and frame structures caused by rotating of unbalanced parts.
- Tip-in moans of resonance vibrations from stressed engine or exhaust system mounts or driveline flexing modes.
