Diagnosis And Testing: Flywheel

Check Dual Mass Flywheel (DMF) runout whenever misalignment is suspected. Measure runout at the outer edge of the flywheel's friction surface with a dial indicator.

Common causes of runout are:

heat warpage
improper machining
incorrect bolt tightening
improper seating on crankshaft flange shoulder
foreign material on crankshaft flange

Minor flywheel scoring is acceptable. Replace the flywheel if scoring is severe.

NOTE:

DO NOT ATTEMPT TO RESURFACE THE FLYWHEEL FOR ANY REASON. IF FLYWHEEL IS SEVERELY SCORED OR DAMAGED REPLACE IT.

Clean the drive plate surface before mounting the flywheel. Dirt and grease on the drive plate surface may cock the flywheel causing excessive runout. Use new bolts when remounting a flywheel and secure the bolts with Mopar™ Lock And Seal or equivalent. Refer to FLYWHEEL, REMOVAL AND INSTALLATION .

ROAD TEST DIAGNOSIS - Observations/evaluations when the vehicle is still drivable (before repair)

CONDITION	POSSIBLE CAUSES	CORRECTION
There is a rattle noise present while the vehicle is moving	There are many factors that can contribute to this noise. The dual mass flywheel is OK and the noise is normal for the application / vehicle. The dual-mass flywheel (DMF) might be damaged.	Try to observe where on the vehicle the noise is coming from (consider other systems than only the DMF). A burst of rattle at low gas pedal position and/or during tip-in / back-out of the gas pedal is OK. Do not replace the DMF. Remove the transmission and inspect the DMF according to the procedures below.
Vibration at idle (vehicle not moving)	Engine issue. Worn clutch disc (damper internals) or transmission input shaft. Damage to or a foreign object on a rotating part in the bellhousing.	Check that service engine or other trouble code is not present. Clear codes if present and ensure they do not return. Push the clutch pedal to the floor and observe if the vibration goes away. Does it return when the pedal is let up? If yes, remove the transmission and check the disc damper for damage and the transmission input shaft for looseness. Replace as necessary. Check the clutch, disc, and DMF for damage or lost parts. Check same for foreign materials present (e.g. mud, grease, debris stuck in one location). Clean or replace parts as necessary.
Vibration during engine start-up or shut-off	Normal operation. DMF is damaged.	The nature of a dual mass flywheel can cause a vibration or thump during engine start or stop. So long as the other vehicle functions of the clutch and flywheel are OK, there is no need to change or inspect the DMF. Abnormal noises such as "pots and pans" or what sounds like a hard hit of a hammer on metal are cause for inspection. Remove the transmission and inspect the DMF according to the procedures below.
Noise during engine start-up or shut-off	Normal operation. DMF is damaged.	The nature of a dual mass flywheel can cause a vibration or thump during engine start or stop. So long as the other vehicle functions of the clutch and flywheel are OK, there is no need to change or inspect the DMF. Abnormal noises such as "pots and pans" or what sounds like a hard hit of a hammer on metal are cause for inspection. Remove the transmission and inspect the DMF according to the procedures below.
Clunk noise during tip-in, back-out of the gas pedal	Normal operation. DMF is damaged.	Some noise is expected during this maneuver, but should only be once per tip-in or back-out event. Try different gas pedal positions and different vehicle speeds (e.g. parking lot speed, 35mph, 60mpg). If the noise changed at one speed versus another, this is normal. Do not change the DMF. A "crunching" noise which is accompanied by a rattle is not OK. Remove the transmission and inspect the DMF according to the procedures below.

VISUAL INSPECTION - Observations of the DMF only (on the back of the engine or on a bench)

CONDITION	POSSIBLE CAUSES	CORRECTION
Noise when the clutch side is moved relative to the engine side (cha-cha noise).	Normal condition. It is by design. Measure the angular free travel. Broken parts inside the flywheel.	No correction. DMF is OK. Up to 19mm or 3/4 inch of angular travel at the outer diameter of the clutch-side mass is allowable. If higher, replace the flywheel. Visually inspect through the holes in the flywheel for cracked components. Worn components are OK. Replace flywheel if internal parts are broken.
The DMF is loose. The clutch side can be moved and the engine side does not move.	Measure the angular free travel.	Up to 19mm or 3/4 inch of angular travel at the outer diameter of the clutch-side mass is allowable. If higher, replace the flywheel.
The DMF is locked-up (clutch side does not move by hand relative to the engine side).	Broken parts inside the flywheel.	Replace flywheel if movement is not possible.
Hot spots on friction surface (leopard or cheetah-like pattern).	Side effect after vehicle use from machining the surface during manufacture of the flywheel.	Vehicle chatter / judder / shudder on launch is not caused by this and presence of the spots is not reason to change the flywheel. Do not replace the flywheel for this condition.
Large hot spots on friction surface (greater than 1 inch in diameter).	Excessive heat / slippage of the clutch.	The actual condition of the spots and overall friction surface must be evaluated to determine if the flywheel should be replaced. Spots are present, but rest of friction surface is still iron-gray or golden colored. Shiny areas may be present. DO NOT replace flywheel Spots are present and the friction surface is blue or purple; the color change is be present at the clutch bolting surface. Replace the flywheel Material smearing is present on the friction surface. Replace the flywheel. Surface cracks are present on the friction surface. Replace the flywheel.
The flywheel is "burnt" or similar.	Excessive heat / slippage of the clutch.	Evaluate the flywheel according to the criteria above for large hot spots.
The flywheel is contaminated (e.g. due to transmission oil leak or hydraulic release system leak).	Leakage from adjoining system.	Do not replace the flywheel. Using a rag or shop towel, apply a suitable cleaner to the rag and clean the friction surface and clutch mounting surface of the flywheel. Do not spray cleaner directly on the flywheel.