- Home »
- Catalog
UnderDog Diesel » 2021, GMC, Sierra 2500
Products for:
- Year: 2021
- Make: GMC
- Model: Sierra 2500
View Universal items for: 2021 GMC Sierra 2500
Browse Products
Description: Fits 2017-2019 Short Bed & Long Bed and 2020-2024 Long Bed (except 2023 & 2024 duallys)
Increase fuel filter capacity and amount of time between filter changes
Anodized billet aluminum fuel...More Details »
Item #: WCF100361
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $245.00
Sale: $237.65
Save: 3%
Save: $7.35
Description: -Your Choice of Custom Exergy Sportsman, 10mm, 12mm, or 14mm CP3 pump specific to this kit
-Billet Aluminum, Black Anodized CP3 Pump Mount Plate
-High Pressure Fuel Line
-High Pressure Rail...More Details »
Item #: WCF100455, WCF100456, WCF100457, WCF100458
Condition:
New
In stock. Ships in 3-5 business days.
This Product cannot ship to the state of California
Price: $2,495.00
Sale: $2,420.15
Save: 3%
Save: $74.85
Description: -Mount Bracket
-Zinc primer & Semi gloss black powder coat finish
Item #: WCF100276
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $62.00
Sale: $60.14
Save: 3%
Save: $1.86
Description: - Gasket Kit for 2017-2023 L5P / 2019+ L5D Duramax OEM/VGT Turbos
Item #: WCF100178
Condition:
New
In stock. Ships in 3-5 business days.
Price: $145.00
Sale: $140.65
Save: 3%
Save: $4.35
Description: Passenger Side Up Pipe
Driver Side Up Pipe
Up Pipe Gaskets (4)
Flows 26% Better than OEM
Made in USA
Item #: WCF100624
Condition:
New
In Stock. Ships in 3-5 business days.
This product cannot ship to California.
Price: $689.00
Sale: $668.33
Save: 3%
Save: $20.67
Description: Flows 27% Better than Stock
True 4" Inlet Turbo Intake with smooth flowing transition to strategically designed anti-surge face which properly engages into turbo compressor cover for optimized...More Details »
Item #: WCF100775
Condition:
New
WCFab Red and WCFab Grey in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
Price: $259.00
Sale: $251.23
Save: 3%
Save: $7.77
Description: CNC Machined Billet Aluminum Plug
Black anodized finish with engraved logo
NO Tuning required, bolt on!
Will fit on stock truck no other modifications or upgrades necessary!
Item #: WCF100473
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $31.00
Sale: $30.07
Save: 3%
Save: $0.93
Description: - Fully TIG Welded, CNC machined billet steel exhaust manifolds
- Finished in Black Ceramic Coat rated for 1800ºF
- Includes new gaskets for manifold to cylinder head, EGR flange, and manifold...More Details »
Item #: WCF100226
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $2,159.00
Sale: $2,094.23
Save: 3%
Save: $64.77
Description: Fully TIG Welded, CNC machined billet steel exhaust manifolds
Finished in Black Ceramic Coat rated for 1800ºF
Includes new gaskets for manifold to cylinder head, EGR flange, and manifold...More Details »
Item #: WCF100373
Condition:
New
In Stock. Ships in 3-5 business days.
This product cannot ship to California.
Price: $1,574.00
Sale: $1,526.78
Save: 3%
Save: $47.22
Description: - Direct Replacement for OEM Thermostat Housing
- Custom Powder Coat Finish
- Cleans up engine bay appearance
- Completes the look when also running one of our Upper Coolant Pipes
Item #: WCF100188
Condition:
New
Gloss White, Gloss Black, WCFab Red, and WCFab Grey in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
Price: $179.00
Sale: $173.63
Save: 3%
Save: $5.37
Description: ARP Up Pipe Bolt kit for 2017+ Duramax. 12 Washers and Bolts for installing both up pipes. Includes ARP Lube
Item #: WCF100199
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $60.00
Sale: $58.20
Save: 3%
Save: $1.80
Item #: WCF100822
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $153.00
Sale: $148.41
Save: 3%
Save: $4.59
Description: 3.5" Steel Down Pipe
High Temp Black Ceramic Coat Finish
Heat Wrap Pre-installed
Catalyst Back - Emissions Compliant
NO TUNING REQUIRED!
Made in USA
Item #: WCF100129
Condition:
New
In Stock. Ships in 3-5 business days.
This product cannot ship to California.
Price: $335.00
Sale: $324.95
Save: 3%
Save: $10.05
Description: ***For Regular Cab Long Bed, Double Cab Short Bed and Crew Cab Short Bed Models***
-LIFETIME WARRANTY against bending or breaking (to original purchaser)
-60" Heavy Duty Bars
-Poly Bushings...More Details »
Item #: WCF100826
Condition:
New
WCFab Red with Standard Brushed Tag, Gloss Black with Standard Brushed Tag, and Gloss White with Standard Brushed Tag in stock and ships in 3-5 business days. 10-15
business day lead time on other colors.
Price: $989.00
Sale: $959.33
Save: 3%
Save: $29.67
Description: ***For Double Cab Long Bed and Crew Cab Long Bed Models***
-LIFETIME WARRANTY against bending or breaking (to original purchaser)
-68" Heavy Duty Bars
-Poly Bushings
-RockJock Johnny Joints...More Details »
Item #: WCF100876
Condition:
New
WCFab Red with Standard Brushed Tag, Gloss Black with Standard Brushed Tag, and Gloss White with Standard Brushed Tag in stock and ships in 3-5 business days. 10-15
business day lead time on other colors.
Price: $989.00
Sale: $959.33
Save: 3%
Save: $29.67
Wehrli Custom Fabrication 2020-2024 Duramax Traction Bar Brackets & Hardware Install Kit - WCF100831
Description: Includes Axle side bolt on and Frame side weld on mounts
Grade 8 Hardware
This part number is mounting hardware only - Bars not included
Powder Coating with zinc primer base coat on axle...More Details »
Item #: WCF100831
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $274.00
Sale: $265.78
Save: 3%
Save: $8.22
Description: Replaces OEM plastic front cover for lower engine bay and cooling stack which is prone to cracking and breaking.
Constructed from heavy gauge aluminum
Uses OEM mounting points
Provides...More Details »
Item #: WCF100459
Condition:
New
Fine Texture Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
Price: $289.00
Sale: $280.33
Save: 3%
Save: $8.67
Description: Aluminum Fabricated Cover
Stainless Hardware
Fill Plug
Custom Powder Coat Finish
Item #: WCF100114
Condition:
New
WCFab Red and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
Price: $374.00
Sale: $362.78
Save: 3%
Save: $11.22
Wehrli Custom Fabrication 2020-2024 GM 2500/3500HD Truck 3/4 in. Front Bumper Spacer Kit - WCF100444
Description: WCFab 3/4" Front Bumper Spacer Kit for 2020-2024 GM 2500/3500 HD Trucks improves aftermarket wheel and tire fitment options by moving front bumper forward and away from front wheels creating more...More Details »
Item #: WCF100444
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $199.00
Sale: $193.03
Save: 3%
Save: $5.97
Wehrli Custom Fabrication 2020-2024 GM 2500/3500HD Truck 3/8 in. Front Bumper Spacer Kit - WCF100446
Description: WCFab 3/8" Front Bumper Spacer Kit for 2020-2024 GM 2500/3500 HD Trucks improves aftermarket wheel and tire fitment options by moving front bumper forward and away from front wheels creating more...More Details »
Item #: WCF100446
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $142.00
Sale: $137.74
Save: 3%
Save: $4.26
Description: Qty. 4 CNC Machined Billet Aluminum Marker Light Delete Plates
High quality mounting hardware
Marker Light Harness Dummy Plugs
Available with or without machined WCFab logo in Raw Aluminum...More Details »
Item #: WCF100390, WCF100391, WCF100392, WCF100393
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $249.00
Sale: $241.53
Save: 3%
Save: $7.47
Description: 3.5 in. Cold Side Intercooler Pipe
Incorporated threaded bung to reinstall OEM Intake Temperature Sensor
Durable Powder Coat Finish
Silicone Boot
T-Bolt Clamps
O-Rings
14g Mandrel...More Details »
Item #: WCF100381
Condition:
New
WCFab Red, WCFab Grey, and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other
colors.
This product cannot ship to California.
Price: $374.00
Sale: $362.78
Save: 3%
Save: $11.22
Description: 4" Intake Pipe
Air Box & Lid Constructed of 10G Aluminum Sheet
Dry Air Filter
Outerwear's Pre-Filter Cover
Hardware
Seal for Connection to Functional Ram Air Port on Hood
High...More Details »
Item #: WCF100702
Condition:
New
This product cannot ship to California.
Price: $629.00
Sale: $610.13
Save: 3%
Save: $18.87
Description: 4" Intake Pipe
3 1/2" Intake Horn
Air Box & Lid Constructed of 10G Aluminum Sheet
Dry Air Filter
Outerwear's Pre-Filter Cover
Hardware
Seal for Connection to Functional Ram Air...More Details »
Item #: WCF100684
Condition:
New
WCFab Red, WCFab Grey, Gloss White, and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
This product cannot ship to California.
Price: $835.00
Sale: $809.95
Save: 3%
Save: $25.05
Description: 4" Intake Pipe
Silicone Hump and Straight Boots
T-bolt Clamps
Powder coating
NO Tuning required, bolt on!
Will fit on stock truck no other modifications or upgrades necessary! More Details »
Item #: WCF100720
Condition:
New
WCFab Red with Standard Brushed Tag, WCFab Grey with Standard Brushed Tag, and Gloss Black with Standard Brushed Tag in stock and ships in 3-5 business days. 10-15
business day lead time on other colors.
This product cannot ship to California.
Price: $225.00
Sale: $218.25
Save: 3%
Save: $6.75
Description: - Auxiliary Coolant Tank for Fuel Cooler
- Black Anodized Billet Aluminum Cap
- Overflow Flow Fitting
- Preformed Hose
- Custom Powder Coat Finish
Item #: WCF100224
Condition:
New
WCFab Red, Bengal Red, Gloss White, and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
Price: $239.00
Sale: $231.83
Save: 3%
Save: $7.17
Description: Coolant Tank
Low Coolant Level Sensor
Black Anodized Billet Aluminum Cap
Over Flow Hose
Coolant Level Sight Glass
Installation hardware
Powder Coating More Details »
Item #: WCF100268
Condition:
New
WCFab Red with Standard Brushed Tag, WCFab Grey with Standard Brushed Tag, Gloss White with Standard Brushed Tag, and Gloss Black with Standard Brushed Tag in stock and
ships in 3-5 business days. 10-15
business day lead time on other colors.
Price: $525.00
Sale: $509.25
Save: 3%
Save: $15.75
Description: 3 in. Hot Side Intercooler Pipe
3.5 in. Cold Side Intercooler Pipe
CNC Machined Flange and black anodized billet aluminum adapter with Double O-Rings provides an improved sealing surface to...More Details »
Item #: WCF100410
Condition:
New
WCFab Red, WCFab Grey and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
This product cannot ship to California.
Price: $679.00
Sale: $658.63
Save: 3%
Save: $20.37
Description: 4 in. Aluminum Intake Pipe
3.5 in. Intake Horn with PCV Port and Surge Ring
Air box enclosure with dry filter assembly and Outerwears pre-filter cover
Installation hardware, 4 in....More Details »
Item #: WCF100414
Condition:
New
WCFab Red, WCFab Grey, Candy Teal, Gloss White, and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
This product cannot ship to California.
Price: $1,515.00
Sale: $1,469.55
Save: 3%
Save: $45.45
Description: 4 in. Aluminum Intake Pipe
3.5 in. Intake Horn with PCV Port and Surge Ring
Air box enclosure with dry filter assembly and Outerwears pre-filter cover
Installation hardware, 4 in....More Details »
Item #: WCF100418
Condition:
New
WCFab Red, Candy Teal, and Gloss White in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
This product cannot ship to California.
Price: $1,829.00
Sale: $1,774.13
Save: 3%
Save: $54.87
Description: Coolant Pipe
Silicone Boots
T-Bolt Clamps
Powder Coating
Item #: WCF100541
Condition:
New
WCFab Red with Standard Brushed Tag, WCFab Grey with Standard Brushed Tag, and Gloss Black with Standard Brushed Tag in stock and ships in 3-5 business days. 10-15
business day lead time on other colors.
Price: $168.00
Sale: $162.96
Save: 3%
Save: $5.04
Description: - Made from thick, cast aluminum
- Includes fasteners, pan, NPT plug, and billet stainless steel Neodymium magnet drain plug
- Finished in your choice of custom powder colors
- Provides 2...More Details »
Item #: WCF100134
Condition:
New
10-15 Business Day Lead Time
Price: $509.00
Sale: $493.73
Save: 3%
Save: $15.27
Description: Fits 2020+ Short Bed
Increase fuel filter capacity and amount of time between filter changes
Anodized billet aluminum fuel filter base
Installs in the same location as the stock...More Details »
Item #: WCF100362
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $245.00
Sale: $237.65
Save: 3%
Save: $7.35
Description: Fits 2020-2024 2500 & 3500 GM HD trucks.
- Replaces ugly OEM aerial antenna
- CNC Machined Billet Aluminum
- Designed to resemble a TIG Torch Cap
- Custom Powder Coat Finish
- Made in USA...More Details »
Item #: WCF100049
Condition:
New
WCFab Red, WCFab Grey, Gloss White and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
Price: $61.00
Sale: $59.17
Save: 3%
Save: $1.83
Description: - Allows you to mount a T4 flange style Turbo for custom build racing applications
- 2" OD Stainless Steel 11 gauge tubing
- Compatible with OEM or WCFAB 2" High Flow Turbo Up Pipes
- Black High...More Details »
Item #: WCF100325
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $859.00
Sale: $833.23
Save: 3%
Save: $25.77
Description: - Adapts T4 Flange Turbine Housing to OEM L5P Duramax Turbo Pedestal for custom turbocharger kits
- Installation Hardware
- Gaskets
- Black Ceramic Coat Finish
- Made in USA
Item #: WCF100256
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $409.00
Sale: $396.73
Save: 3%
Save: $12.27
Item #: WCF206-67
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $41.00
Sale: $39.77
Save: 3%
Save: $1.23
Description: - Parker stainless braided #10 drain and #4 Feed Line
- Plug for OEM feed location in valley
- Fitting for turbo Feed
- Fitting for engine block oil galley
- Turbo drain flange and fitting
-...More Details »
Item #: WCF100372
Condition:
New
In Stock. Ships in 3-5 business days.
This Product cannot ship to the state of California
Price: $309.00
Sale: $299.73
Save: 3%
Save: $9.27
Description: - 12 Specially Selected High Strength Stainless Steel 12-point ARP fasteners
- 12 Matched ARP Stainless Steel Washers
Item #: WCF100217
Condition:
New
In Stock. Ships in 3-5 business days.
Price: $69.00
Sale: $66.93
Save: 3%
Save: $2.07
Engine Oil Filler Cap
Item #: XD477
Condition:
New
Price: $29.95
Starter
Item #: XD533
Condition:
New
Price: $9.95
Engine Head Stud
Item #: XD3017HS
Condition:
New
Price: $574.95
Item #: XD678
Condition:
New
Price: $108.95
Item #: XD679
Condition:
New
Price: $178.95