Donaldson P555776 Secondary Fuel Filter | Cummins X15 & Heavy-Duty Diesel Applications

Donaldson P555776 Secondary Fuel Filter – Advanced Protection for Cummins X15 Fuel Systems

Looking for a high-efficiency replacement fuel filter for your Cummins X15 or heavy-duty diesel engine? The Donaldson P555776 Secondary Fuel Filter is engineered to protect today's high-pressure common rail fuel systems by removing harmful contaminants before they reach sensitive injectors and fuel system components.

Featuring Donaldson's advanced Synteq™ filtration media, the P555776 delivers exceptional contaminant capture, excellent dirt-holding capacity, and reliable fuel flow under demanding operating conditions. This premium spin-on secondary fuel filter helps extend injector life, reduce maintenance costs, and support maximum engine performance.

Commonly used on Cummins X15-powered Freightliner Cascadia, Peterbilt, Kenworth, Western Star, and International trucks, the Donaldson P555776 is trusted by fleets and owner-operators nationwide for dependable fuel system protection. :contentReference[oaicite:0]{index=0}

Key Features

• Premium secondary fuel filtration
• Advanced Donaldson Synteq™ filtration media
• Helps protect high-pressure fuel injectors
• Superior contaminant removal efficiency
• Excellent dirt-holding capacity
• Spin-on design for easy servicing
• Designed for severe-duty trucking applications
• Helps maintain optimal fuel system performance
• Meets or exceeds OEM performance requirements

Specifications

• Part Number: P555776
• Brand: Donaldson
• Filter Type: Secondary Fuel Filter
• Style: Spin-On
• Media: Synteq™
• Outer Diameter: 4.65" (118 mm)
• Height: 8.82" (224 mm)
• Thread Size: M90 x 2

Benefits of Replacing Your Fuel Filter

• Protects expensive fuel injectors
• Reduces fuel system contamination
• Supports proper fuel pressure
• Improves engine efficiency
• Helps prevent injector wear
• Supports maximum uptime
• Promotes long-term engine reliability

Signs Your Fuel Filter Needs Replacement

• Hard starting
• Loss of power under load
• Poor acceleration
• Reduced fuel economy
• Fuel pressure faults
• Check engine light
• Rough idle or hesitation

Common Applications

Frequently used on Cummins X15 engines and other heavy-duty diesel applications operating in regional, vocational, and long-haul trucking environments.

• Freightliner Cascadia
• Peterbilt 579
• Peterbilt 389
• Kenworth T680
• Kenworth W990
• Western Star 5700XE
• International LT Series
• Various Cummins-powered equipment

Cross Reference Numbers

The Donaldson P555776 crosses with the following OEM and aftermarket part numbers:

• Baldwin BF9885
• Fleetguard FF5776
• Luber-Finer LFF6776
• WIX WF10123
• TruckPro DNP555776
• Cummins 2864993
• Cummins 2893612
• Cummins 3685306
• Cummins 4331007
• Cummins 87904MFF5776
• 600123
• 96498
• FF1219
• FTGFF5776
• MH30018
• S26381
• SF10123
• WK12003
• Z1007

These cross references help customers locate replacement fuel filters across multiple manufacturers and platforms. :contentReference[oaicite:1]{index=1}

Why Fuel Filtration Matters on the Cummins X15

Modern Cummins X15 fuel systems operate at extremely high pressures and require exceptionally clean fuel. Contaminants that pass through a worn or low-quality filter can damage injectors, fuel pumps, and emissions components, leading to expensive repairs and unnecessary downtime.

Replacing your secondary fuel filter at recommended service intervals helps maintain proper fuel delivery, improve reliability, and protect your engine investment.