Drop-In Series Fuel System for 25-27 Ram 2500/3500 Cummins 6.7L FASS

The FASS Drop-In Series DIFSRAM5001 fits 2025-2027 Ram 2500 and 3500 trucks with the 6.7L Cummins diesel. It installs in the factory location and works with the Ram OEM in-tank lift pump.

Not compatible with the FASS Fuel Sump Kit. May not fit aftermarket high-capacity fuel tanks; verify clearance before ordering.

Please Note: This is not a lift pump! This is an air separation and filtration system that utilizes your factory in-tank lift pump. Installation of this kit on a cab and chassis may require modifications.

Drop-In Fuel Systems are a plug-and-play filtration upgrade and are not compatible with our Fuel Sump Kit. The system mounts in the factory location and may not fit aftermarket high-capacity fuel tanks; verify clearance before ordering.

No additional items are needed for installation. This drop-in filtration system retains the Ram OEM in-tank fuel pump.

FASS Drop-In Technology: The FASS Drop-In Series Diesel Fuel System is engineered to be the most cost-effective and easiest solution for removing air/vapor from diesel fuel in your diesel fuel injection system. By implementing the extreme water separator (XWS3002) filter our system will provide 2 microns absolute filtration.

Removing entrained air and vapor, Extreme Water Separation, and 2 micron absolute filtration with a Micro-Glass filter element all work together in the FASS Drop-In for Ram to optimize fuel efficiency, restore horsepower, and improve performance across the entire fuel system and engine. And that's only scratching the surface of the benefits FASS brings to your Cummins.

Imagine being able to improve MPG (fuel efficiency), horsepower, increase fuel injection system life, truly balance the engine (smoother operation) with other benefits listed below with an installation time in about 1 hour!

FASS Drop-In Series System Features:

Remove the entrained air and vapor from your diesel fuel and a chain reaction follows.

Patented Air and Vapor Separation - Times 2:

Increases Lubricity to Fuel Injection Components:

At least a 10 percent gain in fuel lubricity under stationary conditions - and that's the floor. Agitation begins the moment the engine does, and vehicle motion compounds it. Restricting filters, higher elevation, heated fuel, and lower fuel levels drive air/vapor higher yet.

The field calls it fuel starvation. Physics calls it entrained air/vapor. Strip it out, and lubricity gains travel well north of 10 percent.

FASS will Triple the life of your fuel injection system - and keep thousands of dollars in your pocket over the long haul.

Optimizes Fuel Efficiency / Horsepower:

Because air and vapor are compressible and fuel is not, they delay fuel entry into the cylinder. Combustion starts late, the burn rate suffers, and the power stroke produces fewer BTUs than it should.

From the Field - FASS optimizes fuel efficiency.

• Customers consistently reporting gains of 6-11 percent, coupled with horsepower gains.
• Customer consistently report the following:
• Truck Only: 1 - 2.5mpg increase
• Loaded: .5 - 1.5mpg increase

True Engine Balancing - Smoother and Quieter Operation:

Air/vapor delays fuel delivery, and it does so inconsistently and unpredictably - throwing the engine out of time. Strip it out, and every cylinder hits its true contribution on every power stroke.

Customers hear it first, then feel it - in the mirrors, in the steering wheel. The engine runs smoother, and less vibration reaches the cab. Less vibration means less stress, and less stress means a longer life.

Consistent Engine Performance with HP Gains:

Diesel engine output depends on precise fuel injection timing, and air/vapor undermines that precision.

Your Cummins engine was rated in a Test Cell - clean, non-agitated fuel, positive flow, roughly 10 percent air in solution. FASS delivers those same conditions in the Real World with the air removed, edging performance just past the Test Cell rating.

Reduces: Regens, Soot/Emissions, EGT's (Turbo Temps), Water/Oil Temps, Oil Consumption:

Shift the fuel timing and you shift the BTUs produced by every power stroke. That single shift ripples outward: how much soot is created, how and when combustion occurs, and how fast heat exits the cylinder as valve and combustion timing drift apart.

Even ring seating depends on it.

Every one of these benefits leads to the same place: Cost. FASS reduces maintenance spending across the board, and while that may sound too good to be true, the physics and the customer reports say otherwise.

• Soot/Emissions: down 18-76.8 percent - plus reductions across CO, CO2, and Oxides of Nitrogen.
• Regens: Many customers report their regen frequency drops by about half.
• EGT's (Turbo Temps): typical stock applications 50-100 degrees F; modified applications 150 degrees F and up, over 200 degrees F.
• Water/Oil Temps: reported 15-25 degrees F.
• Oil Consumption: customers have reported reduced oil consumption.

Peace of Mind - Real Water Separation:

Higher Volume Water Conditions:

Third-party proven to remove over 99 percent of water. In a major contamination event, traditional and OEM cellulose filters pass water straight through to the fuel injection system - and the damage is catastrophic. The FASS Extreme Water Separator dams the flow instead, stopping that water cold.

The benefit, simply put: competitors' filters fill with water, pass that water to the fuel injection system, and you're looking at catastrophic damage and downtime.

Conventional cellulose filters (OEM/direct competitors) - costly when it counts:

• Repair or replace the fuel system - are the parts even available?
• Replace filters and replace fuel - more shop time, more cost.
• Vehicle sits idle, producing nothing - and where are you, loaded or on vacation?

FASS Extreme Water Separator - engineered exclusively for FASS. Cheap insurance against the alternative:

• No fuel system repair or replacement.
• Replace filters and service fuel with FASS filters - that's it.
• Vehicle stays working.

2-Micron Absolute Microglass Filter - 30,000-Mile / 5,000-Gallon Life Expectancy:

Competitors and OEMs use cheap cellulose filters with large micron ratings. Ours is 2-micron absolute microglass - 400 percent more efficient and much higher quality, rated at 1,500 GPH.

To match a cellulose filter to the capability/efficiency of a microglass element you will need a filter four times the size of filter. Our filter has four times the effective filtration, and catches finer debris along the way.

Cold Weather and Fuel Conditioning:

Extreme Cold Weather Operations:

Pair our high-efficiency Micro-Glass fuel filter, rated at 1,500 GPH, with the optional FASS Heater Kit for your climate, and leave traditional OEM gelling and cold-start problems behind.

Drop-In plus FASS Heater Kit. This set up takes 2nd only to it's brother the FASS Titanium Series Plus Fuel System.

Let's take it one step further: want to preheat your FASS System with your phone from the warmth of your home? If you're within about 250 feet, just add FASS Connect to your FASS Heater Kit.

Dependable starts and smooth operation in extreme cold, with no extra modifications. Install the FASS Drop-In System with heater kit about an hour and head into winter with confidence. To Install the FASS Drop-In System with heater kit and head into winter with confidence.

Mass Flow Return (MFR):

FASS keeps positive pressure on the fuel going to your engine and sends the fuel your engine doesn't use back to the tank. That returning fuel has already passed through the FASS filters, with air/vapor, water, and debris removed, so the fuel in your tank is constantly moving and being cleaned.

Every pass makes your fuel cleaner. Your tank holds progressively Polished fuel, and your fuel injection system always sees the cleanest fuel possible.

What's Included In The DIFSRAM5001:

• (1) FASS Drop-In Series Air Separation/Filtration System
• (1) FASS XWS3002XL Extreme Water Separator
• (1) FASS CWS1010 Coalescing Water Separator
• (1) Installation Kit Including all necessary Fittings, Bracketry and Hardware

Why Choose FASS?

OEM filtration was validated in a Test Cell. It was never designed to deliver that same Performance, Productivity, and Protection in the Real World working conditions. That's why the people who build this Great country turn to FASS.

Brad Ekstam, Founder and President

At FASS, we don't rush products to market, we are Striving for Perfection Settling for Excellence. That's why our systems have a failure rate of less than 0.5 percent, and why diesel owners across the country trust us to protect their investments.

Whether you're daily driving your diesel truck or building horsepower, the FASS Drop-In Series Fuel System gives you peace of mind and performance you can feel. Register your system with FASS to activate the limited lifetime warranty.

Fitment Notes:

• Fits 2025, 2026 and 2027 Ram 2500 and Ram 3500 trucks with the 6.7L Cummins diesel.
• Note: Cab and chassis models may require modification.

Details:

• Fits: 2025-2027 Ram 2500/2025-2027 Ram 3500
• Series: Drop-In Series
• Liter: 6.7 Liter
• Fuel Type: Diesel
• Engine: 6.7L Cummins
• Engine Years: 2025-2027
• Engine Manufacturer: Cummins
• Warranty: Limited Lifetime Warranty

Applications:

• 2025-2027 Ram 2500 6.7L Cummins
• 2025-2027 Ram 3500 6.7L Cummins

Order processing times

Most orders will be processed in up to 72 hours. During seasonal times such as Black Friday, order processing time can take up to 5 business days. We appreciate your patience as we prepare your order.

Shipping times 

Shipment dates & lead times will vary based on product availability, product may not be in stock. If you have a question regarding availability please email or call the office to discuss lead times. By completing payment, you have acknowledged the terms and conditions stated. As stock changes daily, we do not hold inventory, first come, first serve.

Currently some brands are experience major delays - contact us or more information.

Local pickup

We currently offer free pickup from our location. You will be notified via email or phone when your item(s) are ready for pickup. 

Returns

We will accept returns within 30 days of original purchase and provide a store credit ONLY, no cash or credit card refunds will be given. All returns are subject to a 20% restocking fee. The product must still be in the original clean packaging, unused and uninstalled. We do not refund shipping and handling charges and the customer is responsible for all return shipping charges. There will be an additional rebox fee charged if the packaging needs to be replaced so please double box your returns. There is no returns of special order, tuners or custom parts.

Cancellations 

Custom parts may not be canceled once your order is placed. Cancelled Orders may be subject to a 15% cancellation fee. All returns must be pre-authorized with a Battle Born Offroad Employee and have an RGA # or they will be returned to you. Refunds will be processed within 48hrs once product is received and in original condition. Most refunds are issued to the original payment method, or by check. Please allow up to 7 business days for store credit to reflect.

Website errors

In the event a product is listed at an incorrect price due to typographical, photographic, or technical error or error in pricing information received from our suppliers, Battle Born Offroad Ltd shall have the right to refuse or cancel any orders placed for product listed at the incorrect price.

Payment processing

By clicking checkout, you agree to have your payment ran anytime after checkout. Some orders may not be charged right away, and you authorize Battle Born Offroad to charge your card up to 365 days after completing your purchase for the maximum amount you paid.

SOME ORDERS DO NOT SHIP RIGHT AWAY

Most Orders will ship within 72hrs. Some parts may not in stock and may incur a 1-52 week time due to limited availability. If you want to check the most up to date lead times on any of these products please email us at info@BattleBornOffroad.net

How can I contact you if I have questions before ordering?
You can call us directly at 702-333-0868, email our support team, or message us on our chat or on social media. We’re here to help you with fitment, installation, and product questions before you commit to a purchase.

Do you price match other retailers?
Yes, we strive to offer the best prices in town. If you find a lower advertised price from an authorized dealer, let us know—we’ll do our best to match or beat it. Some exclusions may apply for clearance or special-order items.

What is your shipping policy and how long will my order take?
We offer free or discounted shipping on most orders over $99. Orders typically ship within 1-3 business days; once shipped, standard transit times depend on your location, but generally most transit time is 2-3 days. Expedited shipping is available at checkout, and offers delivery as quick as 24hrs. Tracking info will be provided once your package is in transit and will be sent electronically to your email. 

Do you offer installation services or do you only sell parts?
Yes, Battle Born Offroad offers professional installation in our Las Vegas shop for ALL products we sell (suspension, lift kits, lighting, etc.). If you’re interested in installation, please hit our live chat button, give us a call at 702-333-0868 or email us to get a quote or get on the schedule. We can assist with shipping your vehicle to us if you are out of state and build trucks from around the country!

What warranty do your products come with?
All of our products come with a manufacturer’s warranty covering defects in materials and workmanship. Warranty durations vary by product and brand. Damage from misuse, improper installation, or off-trail abuse may not be covered. To initiate a claim or have questions, please reach out to us via email at info@battlebornoffroad.net and please submit photos, your order number and a brief description of the issue you are facing. 

Do you offer financing or payment plans?
Yes, we partner with financing providers (Affirm, Shop Pay, SNAP Finance & Koalifi) so you can pay over time. Options like “buy now pay later” or longer-term payment plans may be available. Terms and interest will depend on your credit. Affirm and Shop Pay will be shown during checkout and must be clicked during this process. Other options are offered in store or on the phone, please feel free to call us at 702-333-0868 to discuss more. 

How do you handle damages or defects in shipping?
Please inspect your package immediately upon arrival. If you notice any shipping damage, take clear photos of the damage and packaging and email us within 24 hours of delivery. We will work to make it right, either replacement of the part, or arranging return/reimbursement as needed.

Still have a question?
See all our Frequently Asked Questions or contact us with questions.