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

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2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Parts and Accessories

Crate Engines

Gaskets

Glow Plugs

Head Studs & Main Studs

Heads & Valve Train

Motor Mounts

Oil Pans

Radiators & Cooling Upgrades

Rebuild Kits & Internal Parts

Rods/Pistons/Cams & More

Availability

In Stock 121
Out of Stock 144

Manufacturer

AFE Power 2
ARP 20
BD Diesel 3
Carrillo 1
Cometic 18
Comp Cams 1
DFC Diesel 6
Duramax Tuner 26
Edge Products 17
EFI Live 4
Fleece Performance Products 11
Fluidampr 1
Gator Fasteners 4
HP Tuners 1
Industrial Injection 12
Mahle 15
Merchant Automotive 16
Powerstroke Products 1
PPE 72
SCT Performance 1
Sinister Diesel 5
SoCal Diesel 2
Victor Reinz 6
Wagler Competition Products 8
Wehrli Custom Fab 12

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Make

Dodge RAM 1
Dodge RAM/Ford/GM 1
Ford 1
Ford/Chevrolet/GM/GMC/RAM/Dodge RAM/Universal 19
Ford/Dodge RAM 1
GM 1
GM/Chevrolet 7
GM/Chevrolet/GMC 228
GM/GMC/Chevrolet 4
GM/GMC/Chevrolet/Dodge RAM/RAM/Ford/Universal 1
RAM/Dodge RAM/GMC/Chevrolet 1

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Model

Sierra/Silverado 4
Silverado 1
Silverado/Sierra 229
Super Duty 2
Super Duty/Sierra/Silverado 1

Year

1989-2007 1
1994-2018 1
1999-2007 2
1999-2011 1
1999-2014 1
1999-2016 1
1999-2025 1
2001-2004 2
2001-2005 19
2001-2007 7
2001-2010 29
2001-2011 2
2001-2012 1
2001-2016 85
2001-2018 1
2001-2019 9
2001-2025 4
2001-2026 3
2003-2007 1
2003-2010 1
2004-2007 1
2004-2010 5
2004-2016 2
2004.5-2005 40
2004.5-2006 1
2004.5-2007 1
2004.5-2010 15
2004.5-2016 3
2005-2010 4
2011-2016 1
Universal 20

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Price

$27,677.69

Rating

0-1 231
2-3 2
4+ 9

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Availability

In Stock 121
Out of Stock 144

Manufacturer

AFE Power 2
ARP 20
BD Diesel 3
Carrillo 1
Cometic 18
Comp Cams 1
DFC Diesel 6
Duramax Tuner 26
Edge Products 17
EFI Live 4
Fleece Performance Products 11
Fluidampr 1
Gator Fasteners 4
HP Tuners 1
Industrial Injection 12
Mahle 15
Merchant Automotive 16
Powerstroke Products 1
PPE 72
SCT Performance 1
Sinister Diesel 5
SoCal Diesel 2
Victor Reinz 6
Wagler Competition Products 8
Wehrli Custom Fab 12

Show all Show less

Make

Dodge RAM 1
Dodge RAM/Ford/GM 1
Ford 1
Ford/Chevrolet/GM/GMC/RAM/Dodge RAM/Universal 19
Ford/Dodge RAM 1
GM 1
GM/Chevrolet 7
GM/Chevrolet/GMC 228
GM/GMC/Chevrolet 4
GM/GMC/Chevrolet/Dodge RAM/RAM/Ford/Universal 1
RAM/Dodge RAM/GMC/Chevrolet 1

Show all Show less

Model

Sierra/Silverado 4
Silverado 1
Silverado/Sierra 229
Super Duty 2
Super Duty/Sierra/Silverado 1

Year

1989-2007 1
1994-2018 1
1999-2007 2
1999-2011 1
1999-2014 1
1999-2016 1
1999-2025 1
2001-2004 2
2001-2005 19
2001-2007 7
2001-2010 29
2001-2011 2
2001-2012 1
2001-2016 85
2001-2018 1
2001-2019 9
2001-2025 4
2001-2026 3
2003-2007 1
2003-2010 1
2004-2007 1
2004-2010 5
2004-2016 2
2004.5-2005 40
2004.5-2006 1
2004.5-2007 1
2004.5-2010 15
2004.5-2016 3
2005-2010 4
2011-2016 1
Universal 20

Show all Show less

Price

$27,677.69

Rating

0-1 231
2-3 2
4+ 9

Edge 84130-3 Products Insight CTS3 5 Touch Screen Digital Gauge Monitor | Universal

Edge Products

Edge 84130-3 Products Insight CTS3 5 Touch Screen Digital Gauge Monitor | Universal

SKU: EDG84130-3

Price: $511.95

ARP 100-9910 Ultra-Torque Fastener Assembly Lube (10 oz) | Universal

ARP

ARP 100-9910 Ultra-Torque Fastener Assembly Lube (10 oz) | Universal

SKU: ARP100-9910

Sale price: $18.13
Regular price: $34.58

ARP 230-4201 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP

ARP 230-4201 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: ARP230-4201

Sale price: $640.29
Regular price: $899.99

PPE 114000555 MicroPure Extreme Performance Engine Oil Filter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114000555 MicroPure Extreme Performance Engine Oil Filter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114000555

Sale price: $35.99
Regular price: $39.99

Edge 98620 EAS Starter Kit with EGT Cable | Universal

Edge Products

Edge 98620 EAS Starter Kit with EGT Cable | Universal

SKU: EDG98620

Price: $191.95

Mahle HS54580A Upper Gasket Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle HS54580A Upper Gasket Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCIHS54580A

Price: $300.72

PPE 119000820 Billet Coolant Block Off Plate | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119000820 Billet Coolant Block Off Plate | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119000820

Sale price: $53.99
Regular price: $59.99

PPE 114020000 PCV Crankcase Breather Repair Fitting Set | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114020000 PCV Crankcase Breather Repair Fitting Set | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114020000

Price: $26.99

ARP 100-9911 Ultra-Torque Fastener Assembly Lubricant (20 oz) | Universal

ARP

ARP 100-9911 Ultra-Torque Fastener Assembly Lubricant (20 oz) | Universal

SKU: ARP100-9911

Sale price: $27.26
Regular price: $52.01

EFI Live ACV3 Live Blank AC3 AutoCal Device | Universal

EFI Live

EFI Live ACV3 Live Blank AC3 AutoCal Device | Universal

SKU: EFIACV3

Price: $595

Mahle 55026 Right Side Cylinder Head Gasket (Grade C 1.05mm) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle 55026 Right Side Cylinder Head Gasket (Grade C 1.05mm) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCI55026

Sale price: $54.09
Regular price: $114.43

Mahle 55027 Left Side Cylinder Head Gasket (Grade C 1.05mm) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle 55027 Left Side Cylinder Head Gasket (Grade C 1.05mm) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCI55027

Sale price: $54.09
Regular price: $114.43

ARP 129-2503 Harmonic Balancer Bolt Kit | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax V8

ARP

ARP 129-2503 Harmonic Balancer Bolt Kit | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax V8

SKU: ARP129-2503

Price: $30.42

Edge 85400-200 CTS3 Diesel Evolution Programmer 50 States Legal | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Edge Products

Edge 85400-200 CTS3 Diesel Evolution Programmer 50 States Legal | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: EDG85400-200

Price: $749.95

ARP 230-5401 Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP

ARP 230-5401 Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: ARP230-5401

Sale price: $241.65
Regular price: $460.91

Wehrli 100155 Billet Coolant Heater Core Firewall Fitting | 1999-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100155 Billet Coolant Heater Core Firewall Fitting | 1999-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCF100155

Price: $40.74

SoCal Diesel DSP5LLY DSP5 Switch | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SoCal Diesel

SoCal Diesel DSP5LLY DSP5 Switch | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: SLDDSP5LLY

Price: $55

PPE 119020086 Coolant Drain Tube | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119020086 Coolant Drain Tube | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119020086

Price: $26.99

PPE 119021007 EGR to CAB Coolant Hose | 2004.5-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119021007 EGR to CAB Coolant Hose | 2004.5-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119021007

Price: $12.14

Merchant 10479 Exhaust Manifold to Cylinder Head Bolt Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10479 Exhaust Manifold to Cylinder Head Bolt Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10479

Price: $79.72

EFI Live FS3-GM Flashscan V3 | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

EFI Live

EFI Live FS3-GM Flashscan V3 | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: EFIFS3-GM

Price: $1,025

PPE 119020009 Stainless Steel Heater Hose Connector | 1999-2014 GM Silverado/Sierra 2500HD/3500HD

PPE

PPE 119020009 Stainless Steel Heater Hose Connector | 1999-2014 GM Silverado/Sierra 2500HD/3500HD

SKU: PPE119020009

Price: $19.79

Mahle CS54580 Lower Engine Gasket Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle CS54580 Lower Engine Gasket Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCICS54580

Sale price: $132.67
Regular price: $299.37

PPE 114052020 Black Deep Engine Oil Pan | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114052020 Black Deep Engine Oil Pan | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114052020

Price: $278.99

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FREE SHIPPING ON ALL
ORDERS OVER $70

PRICE MATCH GUARANTEE

BUILD NOW, PAY LATER
FINANCING OPTIONS

30-DAY RETURN SATISFACTION GUARANTEE

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

Can We Help You Find Something?

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

Crate Engines

Gaskets

Glow Plugs

Head Studs & Main Studs

Heads & Valve Train

Motor Mounts

Oil Pans

Radiators & Cooling Upgrades

Rebuild Kits & Internal Parts

Rods/Pistons/Cams & More

Loading products...

Edge 84130-3 Products Insight CTS3 5 Touch Screen Digital Gauge Monitor | Universal

ARP 100-9910 Ultra-Torque Fastener Assembly Lube (10 oz) | Universal

ARP 230-4201 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE 114000555 MicroPure Extreme Performance Engine Oil Filter | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Edge 98620 EAS Starter Kit with EGT Cable | Universal

Mahle HS54580A Upper Gasket Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE 119000820 Billet Coolant Block Off Plate | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE 114020000 PCV Crankcase Breather Repair Fitting Set | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP 100-9911 Ultra-Torque Fastener Assembly Lubricant (20 oz) | Universal

EFI Live ACV3 Live Blank AC3 AutoCal Device | Universal

Mahle 55026 Right Side Cylinder Head Gasket (Grade C 1.05mm) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle 55027 Left Side Cylinder Head Gasket (Grade C 1.05mm) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP 129-2503 Harmonic Balancer Bolt Kit | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax V8

Edge 85400-200 CTS3 Diesel Evolution Programmer 50 States Legal | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP 230-5401 Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli 100155 Billet Coolant Heater Core Firewall Fitting | 1999-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SoCal Diesel DSP5LLY DSP5 Switch | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

PPE 119020086 Coolant Drain Tube | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE 119021007 EGR to CAB Coolant Hose | 2004.5-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant 10479 Exhaust Manifold to Cylinder Head Bolt Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

EFI Live FS3-GM Flashscan V3 | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE 119020009 Stainless Steel Heater Hose Connector | 1999-2014 GM Silverado/Sierra 2500HD/3500HD

Mahle CS54580 Lower Engine Gasket Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE 114052020 Black Deep Engine Oil Pan | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

FREE SHIPPING ON ALL ORDERS OVER $70

PRICE MATCH GUARANTEE

BUILD NOW, PAY LATER FINANCING OPTIONS

30-DAY RETURN SATISFACTION GUARANTEE

DIESEL TRUCK EXPERTS STANDING BY

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ORDERS OVER $70

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