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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Gator Fasteners HSK66 Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
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
SAVE $46
Edge 98608 EAS Temperature Sensor | Universal
IN STOCK
Edge 98608 EAS Temperature Sensor | Universal
Edge 98608 EAS Temperature Sensor | Universal

Edge Products

Edge 98608 EAS Temperature Sensor | Universal

SKU: EDG98608
$80.75
$90.95
SAVE $10.20
ARP 230-6301 Rod Bolt Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
ARP 230-6301 Rod Bolt Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP

ARP 230-6301 Rod Bolt Kit | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: ARP230-6301
$217.92
$415.64
SAVE $197.72
ARP 230-4202 Custom Age 625+ Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
ARP 230-4202 Custom Age 625+ Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP

ARP 230-4202 Custom Age 625+ Head Stud Kit | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: ARP230-4202
$1,727.31
$2,196.48
SAVE $469.17
PPE 119021100 Red Upper & Lower Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119021100 Red Upper & Lower Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119021100 Red Upper & Lower Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119021100
$269.99
PPE 119020100 Upper & Lower Black Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119020100 Upper & Lower Black Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119020100 Upper & Lower Black Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119020100 Upper & Lower Black Coolant Hose Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119020100
$269.99
BD Diesel 1036605 High Idle Control Kit for Trucks with Automatic Trans & Cruise Control | 2004.5-2006 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
IN STOCK
BD Diesel 1036605 High Idle Control Kit for Trucks with Automatic Trans & Cruise Control | 2004.5-2006 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
BD Diesel 1036605 High Idle Control Kit for Trucks with Automatic Trans & Cruise Control | 2004.5-2006 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

BD Diesel

BD Diesel 1036605 High Idle Control Kit for Trucks with Automatic Trans & Cruise Control | 2004.5-2006 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: BDD1036605
$44.95
$48
SAVE $3.05
Fleece FPE-DMAX-CBOP Billet Coolant Block Off Plate | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Fleece FPE-DMAX-CBOP Billet Coolant Block Off Plate | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Fleece FPE-DMAX-CBOP Billet Coolant Block Off Plate | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Fleece FPE-DMAX-CBOP Billet Coolant Block Off Plate | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Fleece Performance Products

Fleece FPE-DMAX-CBOP Billet Coolant Block Off Plate | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: FLCFPE-DMAX-CBOP
$55
$58.79
SAVE $3.79
PPE 118010000 Xtreme Damper Direct Replacement | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 118010000 Xtreme Damper Direct Replacement | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118010000 Xtreme Damper Direct Replacement | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118010000 Xtreme Damper Direct Replacement | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118010000
$539.99
$599.99
SAVE $60
PPE 119000600 Coolant Bypass Tube - Water Pump to Thermostat Housing (Raw) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119000600 Coolant Bypass Tube - Water Pump to Thermostat Housing (Raw) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119000600 Coolant Bypass Tube - Water Pump to Thermostat Housing (Raw) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119000600 Coolant Bypass Tube - Water Pump to Thermostat Housing (Raw) | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119000600
$116.99
Mahle 54580 Right Hand Side Head Gasket Grade A | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Mahle 54580 Right Hand Side Head Gasket Grade A | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle 54580 Right Hand Side Head Gasket Grade A | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCI54580
$88.86
$112.91
SAVE $24.05
PPE 119100100 Fan Clutch Delete Nut | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119100100 Fan Clutch Delete Nut | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119100100 Fan Clutch Delete Nut | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119100100 Fan Clutch Delete Nut | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119100100 Fan Clutch Delete Nut | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119100100
$44.99
$49.99
SAVE $5
PPE 114052001 14mm Billet Hardened Stainless Steel Magnetic Drain Plug for OEM & PPE Engine Oil Pans | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 114052001 14mm Billet Hardened Stainless Steel Magnetic Drain Plug for OEM & PPE Engine Oil Pans | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114052001 14mm Billet Hardened Stainless Steel Magnetic Drain Plug for OEM & PPE Engine Oil Pans | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114052001
$17.99
$19.99
SAVE $2
Merchant 10000 High Performance Motor Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Merchant 10000 High Performance Motor Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10000 High Performance Motor Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10000 High Performance Motor Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10000 High Performance Motor Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10000 High Performance Motor Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10000
$422.63
ARP 100-7533 8MM 12pt Valve Cover Bolt Kit | 2004.5-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
ARP 100-7533 8MM 12pt Valve Cover Bolt Kit | 2004.5-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

ARP

ARP 100-7533 8MM 12pt Valve Cover Bolt Kit | 2004.5-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: ARP100-7533
$148.16
Wehrli 100189 Billet Crankcase PCV Vent Fitting Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Wehrli 100189 Billet Crankcase PCV Vent Fitting Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100189 Billet Crankcase PCV Vent Fitting Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100189 Billet Crankcase PCV Vent Fitting Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100189 Billet Crankcase PCV Vent Fitting Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCF100189
$46.08
PPE 168030160 Engine Mount Kit 60 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 168030160 Engine Mount Kit 60 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030160 Engine Mount Kit 60 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030160 Engine Mount Kit 60 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030160 Engine Mount Kit 60 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 168030160 Engine Mount Kit 60 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE168030160
$269.99
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE168030140
$269.99
PPE 119030130 Polished 304 Stainless Steel Coolant Tube (pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 119030130 Polished 304 Stainless Steel Coolant Tube (pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030130 Polished 304 Stainless Steel Coolant Tube (pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030130 Polished 304 Stainless Steel Coolant Tube (pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030130 Polished 304 Stainless Steel Coolant Tube (pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030130 Polished 304 Stainless Steel Coolant Tube (pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119030130 Polished 304 Stainless Steel Coolant Tube (pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119030130
$197.99
$219.99
SAVE $22
PPE 114001050 Coolant Tube Kit for Internal Oil Cooler Removal | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 114001050 Coolant Tube Kit for Internal Oil Cooler Removal | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114001050 Coolant Tube Kit for Internal Oil Cooler Removal | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114001050 Coolant Tube Kit for Internal Oil Cooler Removal | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114001050
$179.99
$199.99
SAVE $20
Merchant 10233 ARP Rocker Shaft Bolt Kit | 2001-2012 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10233 ARP Rocker Shaft Bolt Kit | 2001-2012 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10233 ARP Rocker Shaft Bolt Kit | 2001-2012 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10233
$24.72
Merchant 10010 Air Bleeder Screw | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Merchant 10010 Air Bleeder Screw | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10010 Air Bleeder Screw | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10010
$10.92
Mahle SH1999S SH-1999S Cam Shaft Bearing Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
Mahle SH1999S SH-1999S Cam Shaft Bearing Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Mahle

Mahle SH1999S SH-1999S Cam Shaft Bearing Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MCISH1999S
$80
Edge 85300 Evolution CS2 | GM/Ford/Dodge Applications
Edge 85300 Evolution CS2 | GM/Ford/Dodge Applications
Edge 85300 Evolution CS2 | GM/Ford/Dodge Applications
Edge 85300 Evolution CS2 | GM/Ford/Dodge Applications
Edge 85300 Evolution CS2 | GM/Ford/Dodge Applications

Edge Products

Edge 85300 Evolution CS2 | GM/Ford/Dodge Applications

SKU: EDG85300
$429.95
$575.95
SAVE $146

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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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