Harmonic Balancer Sliding Back on Crankshaft

A belt chirp sound or metal-to-metal sound may be heard on some 2019-2020 Silverado HD, Sierra, HD and Silverado 4500HD/5500HD/6500HD models equipped with the 6.6L Duramax diesel engine (RPO L5P, L5D).

The outer ring of the harmonic balancer may slide back on the crankshaft and cause a misalignment of the accessory belt. If the outer ring slides back far enough, it may contact the timing cover and oil pans.

Inspect the harmonic balancer, timing cover and oil pans for any damage and replace as needed. (Fig. 10)

Fig. 10

Check for damage to the harmonic balancer due to contact. (Fig. 11)

Fig. 11

Also check for separation of the harmonic balancer’s inner and outer rings. (Fig. 12)

Fig. 12

The damper has a hub that is longer than the inertia ring. Look for a witness mark where the elastomer was originally positioned to identify any movement. (Fig. 13)

Fig. 13

Refer to the appropriate Service Information for the proper procedures to remove the harmonic balancer, timing cover and oil pans.

For additional information, refer to #PIP5742.

– Thanks to John Stempnik

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