Donaldson P550879 Fuel Filter

Fuel Filtration for Heavy-Duty Applications

Donaldson P550879 is a secondary spin-on fuel filter built for heavy-duty diesel fuel systems. It uses synthetic media and a 99% efficiency rating tested to SAE J1985 to help maintain clean fuel flow in demanding service.

Key Features

• Secondary fuel filter with spin-on design for straightforward service replacement.
• Synthetic filter media for consistent filtration performance.
• 99% efficiency rating tested to SAE J1985.
• 7/8-14 UN thread size with 3.66-inch outer diameter.
• Primary application references Cummins 4940647.

Detailed Description

This Donaldson fuel filter is engineered as a secondary filter for diesel fuel delivery systems that require fine filtration after the primary stage. The spin-on style, 174 mm length, and 2.83-inch gasket OD support serviceability in commercial truck applications. It cross-references Monroe Shocks & Struts (e.g., 4940647, FF1173) for the same application. Compatible with applications such as 2012-2014 Freightliner 108SD and 114SD, 2008-2013 Kenworth T270, and 2000-2007 Kenworth T300, this P550879 is used where a secondary fuel filter is specified. The P550879 part number is also associated with 2019 Mack Granite and 2007 Peterbilt 330 fuel filter applications.

What It Is Used For

• Replacing a worn or restricted secondary fuel filter.
• Restoring proper fuel flow through the diesel filtration system.
• Reducing contamination that can affect injector performance.
• Addressing service intervals where a spin-on fuel filter is specified.

Installation Notes and Tips

Verify thread size, gasket dimensions, and filter style before installation. Confirm the application uses a secondary spin-on fuel filter and match the part number P550879 to the service specification. Always follow the vehicle manufacturer’s fuel system service procedure when replacing the filter.

Quality Assurance

Donaldson P550879 is built to a published SAE J1985 efficiency standard and uses synthetic media for filtration consistency. The P550879 part number is listed against multiple heavy-duty truck applications, including Freightliner, Kenworth, International, Peterbilt, and Mack.