2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Engine & Performance

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Crate Engines

Crate Engines

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Gaskets, Gasket Kits & Bearings

Gaskets

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Glow Plugs

Glow Plugs

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Head Studs & Main Studs

Head Studs & Main Studs

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Heads & Valve Train

Heads & Valve Train

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Motor Mounts

Motor Mounts

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Oil Pans

Oil Pans

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Radiators & Cooling Upgrades

Radiators & Cooling Upgrades

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Rebuild Kits & Internal Parts

Rebuild Kits & Internal Parts

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Rods, Pistons, Cams & More

Rods/Pistons/Cams & More

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Mahle 930036055 De-Lipped Cast Piston Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Mahle 930036055 De-Lipped Cast Piston Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle 930036055 De-Lipped Cast Piston Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MLE930036055
$1,733.96
$1,884.74
SAVE $150.78
Merchant 10251 Automotive Glow Plug Nuts (Set of 8) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10251 Automotive Glow Plug Nuts (Set of 8) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10251 Automotive Glow Plug Nuts (Set of 8) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10251
$4.72
Merchant 97321295 Lower Valve Cover Gasket | 2004.5-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 97321295 Lower Valve Cover Gasket | 2004.5-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 97321295 Lower Valve Cover Gasket | 2004.5-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT97321295
$76.72
Tuner 1101A021 DSP5 Switch | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Tuner 1101A021 DSP5 Switch | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Duramax Tuner

Tuner 1101A021 DSP5 Switch | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: DMT1101A021
$40
Edge 98654 EAS Shift On The Fly Accessory | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Edge 98654 EAS Shift On The Fly Accessory | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Edge Products

Edge 98654 EAS Shift On The Fly Accessory | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: EDG98654
$249.95
$281.95
SAVE $32
PPE 228052159 Hard Anodized Billet Aluminum Oil Filter Socket 68mm 14F | Universal
IN STOCK
PPE 228052159 Hard Anodized Billet Aluminum Oil Filter Socket 68mm 14F | Universal
PPE 228052159 Hard Anodized Billet Aluminum Oil Filter Socket 68mm 14F | Universal

PPE

PPE 228052159 Hard Anodized Billet Aluminum Oil Filter Socket 68mm 14F | Universal

SKU: PPE228052159
$35.99
$39.99
SAVE $4
Fleece FPE-DMAX-OCADPT Duramax Oil Cooler Adapter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7
IN STOCK
Fleece FPE-DMAX-OCADPT Duramax Oil Cooler Adapter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7
Fleece FPE-DMAX-OCADPT Duramax Oil Cooler Adapter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7
Fleece FPE-DMAX-OCADPT Duramax Oil Cooler Adapter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7
Fleece FPE-DMAX-OCADPT Duramax Oil Cooler Adapter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7
Fleece FPE-DMAX-OCADPT Duramax Oil Cooler Adapter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7

Fleece Performance Products

Fleece FPE-DMAX-OCADPT Duramax Oil Cooler Adapter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7

SKU: FLCFPE-DMAX-OCADPT
$99
$103.95
SAVE $4.95
Merchant 13939 Valve Guide Seal | 2001-2010 GM 2500HD/3500HD 6.6L Duramax
Merchant 13939 Valve Guide Seal | 2001-2010 GM 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 13939 Valve Guide Seal | 2001-2010 GM 2500HD/3500HD 6.6L Duramax

SKU: MAT13939
$1.39
Merchant 98045060 Grade C Left Side Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 98045060 Grade C Left Side Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 98045060 Grade C Left Side Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT98045060
$99.72
Wagler C6641 Billet Main Caps | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wagler C6641 Billet Main Caps | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wagler Competition Products

Wagler C6641 Billet Main Caps | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCPC6641
$750
Mahle 54598 1.05mm Thick Wave Stopper Head Gasket (Right) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Mahle 54598 1.05mm Thick Wave Stopper Head Gasket (Right) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle 54598 1.05mm Thick Wave Stopper Head Gasket (Right) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCI54598
$183.51
PPE 114002000 Stainless Steel Remote Oil Filter Mount Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114002000 Stainless Steel Remote Oil Filter Mount Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114002000 Stainless Steel Remote Oil Filter Mount Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114002000
$125.99
Fleece FPE-HAR-DMAX-CPS-0416 Crankshaft Position Sensor Pigtail | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Fleece FPE-HAR-DMAX-CPS-0416 Crankshaft Position Sensor Pigtail | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Fleece FPE-HAR-DMAX-CPS-0416 Crankshaft Position Sensor Pigtail | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Fleece FPE-HAR-DMAX-CPS-0416 Crankshaft Position Sensor Pigtail | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Fleece Performance Products

Fleece FPE-HAR-DMAX-CPS-0416 Crankshaft Position Sensor Pigtail | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: FLCFPE-HAR-DMAX-CPS-0416
$21.99
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCF100442
$51.41
PPE 149000135 Heat/Sound Insulator Firewall - Silver | 1999-2007 GM Silverado/Sierra
PPE 149000135 Heat/Sound Insulator Firewall - Silver | 1999-2007 GM Silverado/Sierra
PPE 149000135 Heat/Sound Insulator Firewall - Silver | 1999-2007 GM Silverado/Sierra
PPE 149000135 Heat/Sound Insulator Firewall - Silver | 1999-2007 GM Silverado/Sierra

PPE

PPE 149000135 Heat/Sound Insulator Firewall - Silver | 1999-2007 GM Silverado/Sierra

SKU: PPE149000135
$269.99
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra
IN STOCK
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra

PPE

PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra

SKU: PPE149000124
$269.99
PPE 119000500 Engine Coolant Thermostat Housing | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119000500 Engine Coolant Thermostat Housing | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119000500 Engine Coolant Thermostat Housing | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119000500 Engine Coolant Thermostat Housing | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119000500
$269.99
PPE 114001000 Internal Oil Cooler Removal Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 114001000 Internal Oil Cooler Removal Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114001000 Internal Oil Cooler Removal Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114001000
$269.99
PPE 113061064 Dual Fueler Idler Pulley 4 inch Diameter | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 113061064 Dual Fueler Idler Pulley 4 inch Diameter | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 113061064 Dual Fueler Idler Pulley 4 inch Diameter | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 113061064 Dual Fueler Idler Pulley 4 inch Diameter | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE113061064
$31.49
PPE 110100103 Cast Iron Cylinder Head | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 110100103 Cast Iron Cylinder Head | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 110100103 Cast Iron Cylinder Head | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 110100103 Cast Iron Cylinder Head | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 110100103 Cast Iron Cylinder Head | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE110100103
$1,349.99
Merchant 10263 Oil Cooler Install Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10263 Oil Cooler Install Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10263 Oil Cooler Install Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10263
$65.63
EFI Live LIC-FS2-VIN Tuning FlashScan V2 VIN License | Universal
EFI Live LIC-FS2-VIN Tuning FlashScan V2 VIN License | Universal
EFI Live LIC-FS2-VIN Tuning FlashScan V2 VIN License | Universal

EFI Live

EFI Live LIC-FS2-VIN Tuning FlashScan V2 VIN License | Universal

SKU: EFILIC-FS2-VIN
$125
$129.99
SAVE $4.99
Fleece FPE-DMAX-OC-RED Oil Cap Red | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Fleece FPE-DMAX-OC-RED Oil Cap Red | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Fleece FPE-DMAX-OC-RED Oil Cap Red | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Fleece Performance Products

Fleece FPE-DMAX-OC-RED Oil Cap Red | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: FLCFPE-DMAX-OC-RED
$39.99
Fleece FPE-DMAX-OC-BLU Oil Cap Blue | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Fleece FPE-DMAX-OC-BLU Oil Cap Blue | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Fleece FPE-DMAX-OC-BLU Oil Cap Blue | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Fleece Performance Products

Fleece FPE-DMAX-OC-BLU Oil Cap Blue | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: FLCFPE-DMAX-OC-BLU
$39.99

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DIESEL TRUCK EXPERTS STANDING BY

The 6.6L Duramax LLY under the hood of your 2004.5-2005 GM Sierra/Silverado 2500/3500 may be one of the best and most efficient engines out there, but even the toughest trucks have some power and performance waiting to be unleashed through various performance modifications. Here at Alligator Performance, we carry a selection of cold air intakes, tuners, fuel upgrades, and turbo upgrades to help you get the most out of your diesel engine. Many of these upgrades like the cold air intakes and fuel upgrades even help promote component longevity so you can enjoy long-lasting and consistent performance without compromise. After you've added a few engine upgrades to your custom build, be sure to check out our premium 2004.5-2005 GM 6.6L Duramax LLY Transmission Upgrades to compliment the increase in power you're throwing down! GM Duramax Fitments: 2004, 2005 GM 6.6L Duramax. Submodel Fitments: WT, Custom, LT, LTZ, High Country, 1LT, 2LT, Pro, SLE, SLT, AT4, Denali. Some exceptions apply, please see individual product pages for specific fitments.

GM Duramax>2004.5-2005 6.6L LLY
Tuners & Monitors
Cooling Upgrades
Head Studs & Main Studs
Rods, Pistons & Cams
Heads & Valve Train

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