Application Summary: 2004-2006 Chevrolet Silverado 1500 LS LT Z71 (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 6, 8); 2003-2006 Chevrolet Silverado 1500 HD Base LS LT (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2004-2004 Chevrolet Silverado 2500 LS LT (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2003-2006 Chevrolet Silverado 2500 HD Base LS LT WT (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2003-2006 Chevrolet Silverado 3500 Base LS LT WT (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2004-2006 GMC Sierra 1500 SLT SLE Denali (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8, 6); 2003-2006 GMC Sierra 1500 HD SLT SLE (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2004-2004 GMC Sierra 2500 SLT SLE (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2003-2006 GMC Sierra 2500 HD Base SL SLT WT SLE (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2003-2006 GMC Sierra 3500 Base SL SLT WT SLE (Left and Right) (Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8)