Engine ,A/T - Knock or Rattle Noise From Engine, A/T
TECHNICALBulletin No.: 08-06-01-023C
Date: March 28, 2011
Subject: 4.8L, 6.0L Knock or Rattle Noise from Engine (Replace Flywheel / Flexplate)
Models:
2004-2007 Chevrolet Silverado, GMC Sierra 2500-3500 Series with RPOs LQ4/LR4 & MT1
2004-2007 Chevrolet Express, GMC Savana 2500-3500 Series with RPOs LQ4/LR4 & MT1
2008-2009 Chevrolet Express, GMC Savana 2500-3500 Series with RPOs LY6 & MT1
Equipped with 4L80E (RPO MT1) Automatic Transmission and 4.8L or 6.0L Engine (VINs V, U, K - RPOs LR4, LQ4, LY6)
Supercede:
This bulletin is being revised to update Parts Information. Please discard Corporate Bulletin Number 08-06-01-023B (Section 06 - Engine/Propulsion System).
Concern
Some customers may comment on a rattle or knock noise from the engine. This noise may be caused by a cracked flywheel / flexplate.
Correction
To diagnose this concern, use chassis ears or a stethoscope to determine if the noise is coming from the bell housing. If the source of the noise is detected from the bell housing, remove the transmission to inspect the flywheel for any cracks. If a crack is found, replace the flywheel.
Note
Be sure to remove the spacer from the rear of the crankshaft before installing the new flywheel/flexplate.
Parts Information
Refer to Group 00.666 of the appropriate parts catalog.
Warranty Information
For vehicles repaired under warranty, use the table.
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