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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PPE 114003000 Billet Aluminum Engine Oil Filler Cap | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 114003000 Billet Aluminum Engine Oil Filler Cap | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114003000 Billet Aluminum Engine Oil Filler Cap | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114003000 Billet Aluminum Engine Oil Filler Cap | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114003000 Billet Aluminum Engine Oil Filler Cap | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114003000
$31.49
Wehrli 100025 Coolant Plug for Engine Cover | 2001-2016 GM 2500HD/3500HD 6.6L Duramax
IN STOCK
Wehrli 100025 Coolant Plug for Engine Cover | 2001-2016 GM 2500HD/3500HD 6.6L Duramax
Wehrli 100025 Coolant Plug for Engine Cover | 2001-2016 GM 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100025 Coolant Plug for Engine Cover | 2001-2016 GM 2500HD/3500HD 6.6L Duramax

SKU: WCF100025
$24.25
EFI Live FS3-GM-DC Flashscan V3 | 2001-2016 GMC & RAM Applications
EFI Live FS3-GM-DC Flashscan V3 | 2001-2016 GMC & RAM Applications

EFI Live

EFI Live FS3-GM-DC Flashscan V3 | 2001-2016 GMC & RAM Applications

SKU: EFIFS3-GM-DC
$1,891.27
ARP 400-7533 12pt Valve Cover Bolt Kit | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
ARP 400-7533 12pt Valve Cover Bolt Kit | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP

ARP 400-7533 12pt Valve Cover Bolt Kit | 2004-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: ARP400-7533
$164.12
PPE 119020092 2" inch OEM Coolant Hose Drain 1/4 inch Bung | Universal
IN STOCK
PPE 119020092 2" inch OEM Coolant Hose Drain 1/4 inch Bung | Universal
PPE 119020092 2" inch OEM Coolant Hose Drain 1/4 inch Bung | Universal

PPE

PPE 119020092 2" inch OEM Coolant Hose Drain 1/4 inch Bung | Universal

SKU: PPE119020092
$26.99
$29.99
PPE 114000565 Oil Filter - Micropure Extreme Performance with Torqstop Technology | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 114000565 Oil Filter - Micropure Extreme Performance with Torqstop Technology | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114000565 Oil Filter - Micropure Extreme Performance with Torqstop Technology | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114000565 Oil Filter - Micropure Extreme Performance with Torqstop Technology | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114000565 Oil Filter - Micropure Extreme Performance with Torqstop Technology | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114000565 Oil Filter - Micropure Extreme Performance with Torqstop Technology | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114000565
$35.99
$39.99
Edge 85401-201 Evolution CTS3 50 State Legal Programmer | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Edge 85401-201 Evolution CTS3 50 State Legal Programmer | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Edge 85401-201 Evolution CTS3 50 State Legal Programmer | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Edge 85401-201 Evolution CTS3 50 State Legal Programmer | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Edge 85401-201 Evolution CTS3 50 State Legal Programmer | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Edge Products

Edge 85401-201 Evolution CTS3 50 State Legal Programmer | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: EDG85401-201
$849.95
$956.95
Sinister SD-BD585 Black Diamond Driver Side Grade C Head Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Sinister SD-BD585 Black Diamond Driver Side Grade C Head Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Sinister Diesel

Sinister SD-BD585 Black Diamond Driver Side Grade C Head Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: SINSDBD585
$120.99
Sinister SD-BD582 Black Diamond Passenger Side Grade C Head Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Sinister SD-BD582 Black Diamond Passenger Side Grade C Head Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Sinister Diesel

Sinister SD-BD582 Black Diamond Passenger Side Grade C Head Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: SINSDBD582
$120.99
PPE 119022100 Blue Upper & Lower Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119022100 Blue Upper & Lower Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119022100 Blue Upper & Lower Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119022100
$269.99
Wagler C6664 Push Rods | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wagler C6664 Push Rods | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wagler Competition Products

Wagler C6664 Push Rods | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCPC6664
$442.08
PPE 168030150 Engine Mount Kit 50 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 168030150 Engine Mount Kit 50 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030150 Engine Mount Kit 50 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030150 Engine Mount Kit 50 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030150 Engine Mount Kit 50 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 168030150 Engine Mount Kit 50 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE168030150
$269.99
PPE 118034250 Harmonic Balancer Bolt 12 Point | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118034250 Harmonic Balancer Bolt 12 Point | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118034250 Harmonic Balancer Bolt 12 Point | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118034250 Harmonic Balancer Bolt 12 Point | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118034250
$26.99
Merchant 19210615 Engine Oil Cooler Assembly | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 19210615 Engine Oil Cooler Assembly | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 19210615 Engine Oil Cooler Assembly | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 19210615 Engine Oil Cooler Assembly | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT19210615
$799.73
Mahle MS2218P Main Bearing Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Mahle MS2218P Main Bearing Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle MS2218P Main Bearing Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCIMS2218P
$88.44
$110.31
Merchant 10549 Water Pump Kit with Cover | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10549 Water Pump Kit with Cover | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10549 Water Pump Kit with Cover | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10549
$279.75
HP Tuners M04-000-00 Computer Programmers | Universal
IN STOCK
HP Tuners M04-000-00 Computer Programmers | Universal
HP Tuners M04-000-00 Computer Programmers | Universal
HP Tuners M04-000-00 Computer Programmers | Universal
HP Tuners M04-000-00 Computer Programmers | Universal
HP Tuners M04-000-00 Computer Programmers | Universal

HP Tuners

HP Tuners M04-000-00 Computer Programmers | Universal

SKU: HPTM04-000-00
$399.99
PPE 119000630 Coolant Bypass Tube - Water Pump to Thermostat Housing (Polished) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119000630 Coolant Bypass Tube - Water Pump to Thermostat Housing (Polished) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119000630 Coolant Bypass Tube - Water Pump to Thermostat Housing (Polished) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119000630 Coolant Bypass Tube - Water Pump to Thermostat Housing (Polished) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119000630
$116.99
PPE 119020010 Engine to CAB Coolant Hose | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119020010 Engine to CAB Coolant Hose | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119020010 Engine to CAB Coolant Hose | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119020010
$11.69
Mahle 54583Left Side Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Mahle 54583Left Side Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle 54583Left Side Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCI54583
$88.86
$188.38
PPE 114000559 Engine Oil Filter Socket | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 114000559 Engine Oil Filter Socket | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114000559 Engine Oil Filter Socket | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114000559 Engine Oil Filter Socket | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114000559 Engine Oil Filter Socket | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114000559
$35.99
Merchant 331304A Transfer Case Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 331304A Transfer Case Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 331304A Transfer Case Gasket | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT331304A
$4.92
Gator Fasteners HSK66 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners HSK66 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners HSK66 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners HSK66 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners HSK66 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Gator Fasteners

Gator Fasteners HSK66 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: GTFHSK66
$549.99
$595.99
Edge 98617 EAS Competition Kit | Universal
IN STOCK
Edge 98617 EAS Competition Kit | Universal
Edge 98617 EAS Competition Kit | Universal

Edge Products

Edge 98617 EAS Competition Kit | Universal

SKU: EDG98617
$584.95
$658.95

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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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