FASS Drop-In Series Fuel System – for 2017 to 2025 GMC/Chevrolet, Duramax 6.6L
THIS IS NOT A LIFT PUMP! This is an air separation/filtration system that utilizes your factory lift pump.
The DIFSL5P1001 Fits: 2017-2025 Crew Cab Long Bed L5P Duramax
The DIFSL5P1001 Fits: 2017-2019 Crew Cab Short Bed L5P Duramax
The DIFSL5P2001 Fits: 2020-2025 Crew Cab Short Bed L5P Duramax
Note: Installation on cab and chassis may require modifications. Drop In Fuel Systems are plug and play filtration upgrades and not compatible with Fuel Sump Kits. System retains the OEM in tank fuel pump.
The FASS Drop In Series Diesel Fuel System is engineered to be the most effective filtration solution for the 6.6L Duramax. Backed by a limited lifetime warranty, it protects against issues caused by fuel contamination.
If you drive a GMC/Chevrolet with a Duramax diesel engine and want better fuel filtration, improved reliability, and injector protection without an external frame mounted pump, this is the perfect solution.
The FASS Drop-In Series System for the L5P Duramax replaces the plastic OEM single filter housing with a 6061-T6 billet aluminum American made dual filter housing. This system utilizes the OEM water separator element in conjunction with our 2 micron Extreme Water Separator. Utilizing the OEM water separator element allows the water-in-fuel sensor to operate correctly, notifying you before the water reaches the clean side of the fuel filter element. Many other systems on the market utilize a spin-on water separator that places the WIF sensor on the clean side of the filter meaning by the time your WIF light is triggered, it’s too late! Our Extreme Water Separator provides the final particulate and water filtration filtering particulates down 2 microns and removes over 99% free and emulsified water. OEM filtration provides a 5 micron filtration rating allowing the larger particulates to pass through to your injection system.
Reliability, Simplicity, Protection
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Supports Stock & Modified Duramax: Plenty of fuel for stock and modified GMCs and Chevrolets.
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Injector Protection: Will triple the life of your injectors and injection pump.
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FASS Filtration: Optimizes combustion, restores horsepower, maximizes MPG (results vary).
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Limited Lifetime Warranty: Register your FASS system for coverage.
Advanced Filtration Technology
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Water Separation: 3rd‑party proven to eliminate over 99% of water.
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Air/Vapor Removal: Eliminates entrained air and vapor that damage injection systems.
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2 Micron Absolute Microglass Filtration: Removes smaller debris than OEM filters.
Key Benefits
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Improves Reliability: Triples the injection system life.
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Maximized Horsepower: Improved fuel atomization and restored timing.
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Optimized MPG: More efficient combustion (results vary).
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Peace of Mind: Extreme Water Separator acts as a fail‑safe.
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Cold Weather Confidence: Dependable starts in extreme cold.
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Cleaner Operation: Reduces DPF regens and soot.
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Improves Fuel Lubricity: At least 10% improvement.
Key Features
- Only drop in 6.6L Duramax filtration system that retains OEM water in fuel light.
- Only drop in 6.6L Duramax filtration system with air separation.
- 100% drop in installation; no modifications needed.
- Retains factory in tank lift pump.
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Performance Radius Cuts (PRC): Smoother internal fuel flow.
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2 micron absolute filtration rating: Captures finer debris than OEM.
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Removes over 99% of water: 3rd party verified.
- Patented air/vapor removal process.
- Heater options available for cold weather.
- Limited Lifetime Warranty (with registration).
What’s Included In The DIFSL5P FASS Drop-In Series:
- (1) FASS Drop-In Series Air Separation/Filtration System
- (1) FASS XWS3002 Extreme Water Separator
- (1) Installation Kit Including Fittings, Bracketry, and Hardware
Why Choose FASS?
FASS designs fuel systems with longevity and real‑world performance in mind. The Drop‑In Series offers proven filtration and injector protection without altering the OEM configuration, ideal for daily drivers and work trucks.
Vehicle Fitment by Year
- 2017 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2017 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2017 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2017 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2018 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2018 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2018 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2018 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2019 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2019 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2019 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2019 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2020 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2020 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2020 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2020 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2021 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2021 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2021 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2021 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2022 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2022 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2022 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2022 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2023 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2023 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2023 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2023 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2024 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2024 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2024 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2024 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2025 GMC Sierra 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2025 GMC Sierra 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
- 2025 Chevrolet Silverado 2500HD/3500HD Crew Cab Short Bed – 6.6L Duramax (L5P)
- 2025 Chevrolet Silverado 2500HD/3500HD Crew Cab Long Bed – 6.6L Duramax (L5P)
