Clutch: Testing and Inspection
CLUTCH PROBLEM CAUSESFluid contamination is a major cause of clutch problems. Oil, grease, water or fluid on the clutch contact surfaces will cause faulty operation.
During clutch inspection, note if any components are contaminated with oil, grease, clutch linkage hydraulic fluid or water/road splash.
Oil contamination indicates a leak at either the engine crankshaft rear main seal or transmission input shaft. Oil leakage produces a residue of oil on the housing interior and on the clutch cover and flywheel. Heat buildup caused by slippage between the cover, disc and flywheel cause the oil residue to bake onto these components. This baked on residue ranges in color from light brown to black.
Grease contamination is usually caused by over lubrication. During clutch service apply only a small amount of grease to the components requiring lubrication.
Clutch components requiring lubrication are the splines in the clutch disc hub and clutch pedal pivot bore and bushings. Transmission components requiring lubrication are the input shaft splines and the release bearing slide surface of the front bearing retainer. Do not apply grease to any part of the clutch cover, disc or release bearing.
Hydraulic clutch fluid contamination is caused by damaged clutch fluid lines or a leaking clutch slave cylinder. Most clutch fluid leaks will be noted and corrected before severe contamination occurs.
Road splash is caused by driving the vehicle through deep water puddles. Water contamination will usually produce rust on the flywheel, clutch disc or the input splines of the transmission. There may also be mud or dirt inside of the bell housing.
CLUTCH MISALIGNMENT
Clutch components must be in proper alignment with the crankshaft and transmission input shaft. Misalignment caused by excessive run-out or warpage of any clutch component will cause grab, chatter and/or improper clutch release.
FLYWHEEL MISALIGNMENT
Common causes of flywheel misalignment are:
- Incorrect bolt tightening
- Mounting the flywheel on a dirty crankshaft flange
- Improper seating on the crankshaft flange shoulder
- Heat warpage
- Loose flywheel to crankshaft bolts
The flywheel should be replaced if warped or overheated. Do not machine the face of the flywheel to correct a warped or overheated condition.
Clean the crankshaft flange and its mating surface on the flywheel before assembling. Dirt and/or grease in this area could cause the flywheel to misalign when installing.
Use new bolts when mounting flywheel and secure the bolts with Mopar Lock and Seal or equivalent. Tighten flywheel bolts to specified torque only. Over tightening can distort the flywheel causing run out.
CLUTCH COVER AND DISC RUNOUT
Check the clutch disc before installation, even if it is a new disc. Face run out of the disc should not exceed 0.5 mm (0.020 inch). Run out should be checked 1/4 inch from the outer edge of the disc. If run out is excessive obtain another disc.
Check the condition of the clutch cover (pressure plate) before installation. A warped cover or diaphragm spring will cause incomplete release or engagement of the clutch. Use care when handling the clutch cover (pressure plate) or disc. An impact can distort the clutch cover (pressure plate), release fingers, diaphragm spring, or the clutch disc.
Use an alignment tool when positioning the disc on the flywheel. The tool prevents accidental misalignment which could cause cover distortion or disc damage.
A common cause of clutch cover distortion is improper bolt tightening. To avoid warping the clutch cover (pressure plate), tighten bolts in a crisscross pattern one or two turns at a time until the specified torque is reached.
CLUTCH CHATTER
For all clutch chatter complaints, do the following:
1. Check for loose, misaligned, or broken engine and transmission mounts. If present, they should be corrected at this time. Test vehicle for chatter. If chatter is gone, there is no need to go any further. If chatter persists:
2. Check for proper hydraulic clutch linkage operation.
3. Remove transmission.
4. Check to see if the release bearing is sticky or binding. Replace bearing, if needed.
5. Check flywheel and clutch cover (pressure plate) for contamination (dirt, oil) or scored. Replace flywheel and/or pressure plate, if required.
6. Check to see if the clutch disc hub splines are damaged. Replace with new disc if required.
7. Check for uneven wear on clutch fingers. Replace clutch cover (pressure plate) if required.
8. Check pilot bearing located in the crank shaft of the engine. Also check the input shaft nose for nicks burrs or damage. Replace parts as required.
9. To reinstall, See Clutch Cover and Disc Removal and Installation Procedure.