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

Loading products...
Filter
281 products
Sort by:
Best selling
Mahle CB1805H Standard Rod Bearing Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Mahle CB1805H Standard Rod Bearing Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle CB1805H Standard Rod Bearing Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCICB1805H
$35.52
$44.30
SAVE $8.78
Cometic C15043 17-Bolt Fiber Oil Pan Gasket Lower - .060 inch | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Cometic C15043 17-Bolt Fiber Oil Pan Gasket Lower - .060 inch | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Cometic

Cometic C15043 17-Bolt Fiber Oil Pan Gasket Lower - .060 inch | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: COMC15043
$19.03
ARP 900-0550 4.005 Bore Ring Compressor | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
ARP 900-0550 4.005 Bore Ring Compressor | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP

ARP 900-0550 4.005 Bore Ring Compressor | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: ARP900-0550
$97.13
Edge 98607 0-100 PSIG EAS Pressure Sensor | Universal
IN STOCK
Edge 98607 0-100 PSIG EAS Pressure Sensor | Universal

Edge Products

Edge 98607 0-100 PSIG EAS Pressure Sensor | Universal

SKU: EDG98607
$220.95
$248.95
SAVE $28
Industrial 44B801 130lb Valve Spring Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial 44B801 130lb Valve Spring Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial 44B801 130lb Valve Spring Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial 44B801 130lb Valve Spring Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial 44B801 130lb Valve Spring Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B801 130lb Valve Spring Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: IIS44B801
$873.92
Wehrli 100645 OEM Placement Coolant Tank Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Wehrli 100645 OEM Placement Coolant Tank Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100645 OEM Placement Coolant Tank Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100645 OEM Placement Coolant Tank Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100645 OEM Placement Coolant Tank Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100645 OEM Placement Coolant Tank Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCF100645-GB
From $474.33
Gator Fasteners MSK667Y Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners MSK667Y Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners MSK667Y Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners MSK667Y Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Gator Fasteners MSK667Y Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Gator Fasteners

Gator Fasteners MSK667Y Main Stud Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: GTFMSK667Y
$279.99
$350
SAVE $70.01
Tuner DT8120010104000 Street Tune incl EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
Tuner DT8120010104000 Street Tune incl EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

Duramax Tuner

Tuner DT8120010104000 Street Tune incl EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: DMTDT8120010104000
$808
Tuner DT1120010008000 Transmission Tune Only for EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
Tuner DT1120010008000 Transmission Tune Only for EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

Duramax Tuner

Tuner DT1120010008000 Transmission Tune Only for EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: DMTDT1120010008000
$300
DFC Diesel 6604505LLYTKSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY Topkick 6
DFC Diesel 6604505LLYTKSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY Topkick 6
DFC Diesel 6604505LLYTKSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY Topkick 6

DFC Diesel

DFC Diesel 6604505LLYTKSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY Topkick 6

SKU: DDU6604505LLYTKSOASBCC
$12,576.19
DFC Diesel 6604505LLYSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY
DFC Diesel 6604505LLYSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY
DFC Diesel 6604505LLYSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY

DFC Diesel

DFC Diesel 6604505LLYSOASBCC Speed of Air Short Block (STD/AUTO) Callies Crankshaft | 2004.5-2005 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY

SKU: DDU6604505LLYSOASBCC
$12,576.19
Industrial 44B112 Coated & De-Lipped X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B112 Coated & De-Lipped X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B112 Coated & De-Lipped X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B112 Coated & De-Lipped X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B112 Coated & De-Lipped X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B112
$2,327.95
$2,399.95
SAVE $72
Industrial 44B111 Coated & De-Lipped X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B111 Coated & De-Lipped X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B111 Coated & De-Lipped X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B111 Coated & De-Lipped X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B111 Coated & De-Lipped X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B111
$2,327.95
$2,399.95
SAVE $72
Industrial 44B110 Coated & De-Lipped X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B110 Coated & De-Lipped X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B110 Coated & De-Lipped X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B110 Coated & De-Lipped X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B110 Coated & De-Lipped X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B110
$2,327.95
$2,399.95
SAVE $72
Industrial 44B109 Coated & De-Lipped X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B109 Coated & De-Lipped X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B109 Coated & De-Lipped X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B109 Coated & De-Lipped X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B109 Coated & De-Lipped X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B109
$2,327.95
$2,399.95
SAVE $72
Industrial 44B104 X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B104 X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B104 X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B104 X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Alligator Performance

Industrial 44B104 X-Series Piston Kit (.040) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B104
$1,842.95
$1,899.95
SAVE $57
Industrial 44B103 X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B103 X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B103 X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B103 X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B103 X-Series Piston Kit (.030) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B103
$1,842.95
$1,899.95
SAVE $57
Industrial 44B102 X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B102 X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B102 X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B102 X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B102 X-Series Piston Kit (.020) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B102
$1,842.95
$1,899.95
SAVE $57
Industrial 44B101 X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B101 X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B101 X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
Industrial 44B101 X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 44B101 X-Series Piston Kit (Standard) | 2001-2016 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: IIS44B101
$1,842.95
$1,899.95
SAVE $57
Mahle 54597 1.05mm Thick Wave Stopper Head Gasket (Left) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Mahle 54597 1.05mm Thick Wave Stopper Head Gasket (Left) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle 54597 1.05mm Thick Wave Stopper Head Gasket (Left) | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCI54597
$183.51
ARP 430-0203 SS 12pt Upper Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM
ARP 430-0203 SS 12pt Upper Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM

ARP

ARP 430-0203 SS 12pt Upper Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM

SKU: ARP430-0203
$79.06
ARP 430-0202 SS 12pt Lower Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM
ARP 430-0202 SS 12pt Lower Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM

ARP

ARP 430-0202 SS 12pt Lower Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM

SKU: ARP430-0202
$100.25
ARP 130-0203 Upper Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM
ARP 130-0203 Upper Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM

ARP

ARP 130-0203 Upper Rocker Cover Bolt Kit | 2004.5-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax LLY/LMM

SKU: ARP130-0203
$56.22
Wehrli 100443 Black Anodized Billet Oil Fill Tube Cap | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Wehrli 100443 Black Anodized Billet Oil Fill Tube Cap | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100443 Black Anodized Billet Oil Fill Tube Cap | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100443 Black Anodized Billet Oil Fill Tube Cap | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100443 Black Anodized Billet Oil Fill Tube Cap | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100443 Black Anodized Billet Oil Fill Tube Cap | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCF100443
$51.41

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?

Give us a call: +1-208-719-7400

Chat With Us