Exhaust Moan Drone Vibration At Approximately 1700 RPMs - keywords 6.6 LLY LBZ resonance noise buzz
| Subject: | Exhaust Moan Drone Vibration At Approximately 1700 RPM's |
| Models: | 2004-2007 Chevrolet Silverado Classic 2500HD/3500 Series |
| 2004-2007 GMC Sierra Classic 2500HD/3500 Series |
| with 6.6L Diesel Engine (VIN 2 or D - RPO LLY or LBZ) |
This PI is being superseded to update models. Please discard PIT3457C.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Full size trucks equipped with the 6.6L LLY and or LBZ engine may have an exhaust moan/drone/vibration concern at approximately 1700 RPMs
Recommendation/Instructions:
If working on a 2004-2005 crew cab short box pickup follow bulletin 05-06-05-002. All other models have had success reducing the concern by installing two exhaust dampeners, part number 10199232, five inches forward of the catalytic converter.
Note: If working on a 2006 or 2007 crew cab short box pickup or after performing bulletin 05-06-05-002 on a 2004-2005 crew cab short box and the concern is not corrected to the owners satisfaction, two exhaust dampeners, part number 10199232, can be added 17 1/2 inches forward of the catalytic converter.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
