Duramax 6.6L Hollow And Solid Pushrod Interchangeability - keywords arm broken diesel hole engine noise lube lubrication push repair rocker rocker arm rod tick tube valve valvetrain
| Subject: | Duramax 6.6L Hollow and Solid Pushrod Interchangeability |
| Models: | 2001-2008 Chevrolet Express, Kodiak, Silverado Classic |
| 2007-2008 Chevrolet Silverado |
| 2001-2008 GMC Savana, Sierra Classic, Topkick |
| 2007-2008 GMC Sierra |
| Equipped with 6.6 diesel engine RPO codes LB7 LBZ LLY or LMM |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
During a engine repair a dealer technician may need to replace a pushrod.
There are two pushrods available for the Duramax diesel engines. The pushrods available are either hollow (lubrication hole through the center of pushrod) or solid (no lube hole in the center of the pushrod).
Recommendation/Instructions:
On production LB7 engines through 2004, oil flowed through the rocker arms, through the passage in the valve adjusting screw, and into the hollow pushrods where it was directed to the valve lifters.
Beginning with the 2004.5 engine (LLY), lifters with hardened rollers were used, and did not require hollow pushrods for the additional oil flow. However, hollow pushrods were used in production until approximately the start of the 2006 model year, after which the hole in the pushrod was removed.
The hollow pushrods can be used for any model year Duramax Diesel Engine.
The solid pushrods without holes, should only be used for the 2004 and above LBZ LLY and LMM engines with hardened roller lifters.
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.
