GM/Chevrolet 6.6 403 - Duramax Diesel - Production Years 2004-2005

Description

In 2004, Chevy/GM introduced the 6.6 403 LLY, a diesel engine designed to improve the motor’s performance.

The LLY boasted 310 horsepower. Early models featured 520 pound-feet of torque, later models of the motor boasted 605 pound-feet of torque. It is a straight upgrade over the LB7, including the injector system of the 2001-2004 models, which built a reputation for fuel injection failures.

The 2004-2005 403s are fitted with emissions controlling technology designed to help the newer 403s adhere to emissions regulations in the United States.

The 2004-2005 Chevy/GM 403s are known to overheat, and this was especially the case when trucks were under load, either towing or with a full bed.

Engineers speculate that this overheating may have been caused by restricted airflow or improper cooling system maintenance, but there is no single cause for this motor’s tendency to overheat.

Makes & Models

Introduced in the middle of the 2004 production cycle, the LLY was used in Chevrolet/GM Heavy-Duty pickups. The 2004-2005 models boasted 310 horsepower and 520 pound-feet of torque, and the 2006 model produced 310 horsepower and 605 pound-feet of torque.

Models include

• 2004-2005 Chevrolet Silverado HD
• 2004-2005 GMC Sierra HD
• 2006 Chevrolet Silverado HD
• 2006 GMC Sierra HD

2004-2005 Chevy 403ss from MABBCO

• Short Block Chevy 403s - 2004-2005
• Long Block Chevy 403s - 2004-2005

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