Duramax LLY – DAMPER AND FLYWHEEL SERVICE

The flywheel can be immersed in cleaning solvent. However, the torsional damper should only be wiped clean with a cloth wetted with parts cleaner. The damper has a rubber composite insulator (Figure 2-146). This insulator can be damaged by immersion in some cleaning solutions.

Inspect the damper insulator ring (Figure 2-146). Replace the damper if the ring is cracked, distorted, protruding, or loose (hub can be turned independently of outer shell). Also check the hub bore, keyway, and seal surface. Minor nicks or scratches can be smoothed with 320 grit emery but replace the damper if these surfaces are severely scored, or cracked. Clean the bolt hole threads with a tap if necessary.

CAUTION: 6.5L diesel engines are externally balanced. The torsional damper is an integral part of the balancing mechanism. Never use a solid, or similar non-recommended damper as this practice can result in a broken crankshaft. Use factory replacement dampers only.

Inspect the flywheel carefully (Figure 2-147). Look for worn, chipped, or broken ring gear teeth and check the hub for cracks at the mounting bolt holes. Place the flywheel on a flat surface and check the body for warping, distortion, or cracks at the converter attaching bolt holes. Replace the flywheel if it exhibits any of the foregoing conditions.

NOTE: The ring gear is not serviced separately. It is only available as part of a new flywheel.