FAG SS2578 Differential Pinion Seal - Front Outer, Rear or Rear Outer

FAG SS2578 Differential Pinion Seal

The FAG SS2578 differential pinion seal is built for driveline sealing applications that demand accurate dimensions and durable sealing materials. It uses Viton sealing material with a metal spring and auxiliary lip design to help maintain a tight seal at the pinion area while keeping contaminants out.

Compatible with a wide range of Ford, Lincoln, Mercury, Mazda, and select other vehicle applications, this seal is a direct-fit option for many rear and front axle service jobs. The FAG SS2578 is also referenced by cross numbers used in the same application.

Key Features

• Part number: SS2578
• Seal type: metal, spring, auxiliary lip
• Sealing material: Viton
• Bore diameter: 2.777 in. / 70.536 mm
• Seal outside diameter: 2.783 in. / 70.688 mm
• Seal width: 1.812 in. / 46.025 mm
• Designed to help protect driveline components from dirt, dust, and moisture
• Built to help retain lubricant at the bearing and seal interface

Detailed Description

FAG designs seals to meet vehicle manufacturer specifications using high-quality materials and application-specific engineering. The SS2578 differential pinion seal follows that approach with a Viton sealing element and a metal spring-assisted profile for consistent sealing performance in demanding axle environments. Its dimensions are specified for precise fitment, including a 2.777-inch bore diameter, 2.783-inch outside diameter, and 1.812-inch width.

This seal is used across many driveline and axle applications, including Ford F-150, Ford Expedition, and Lincoln Navigator service needs, along with numerous other rear and front axle configurations. This part cross-references Anchor 3604 and Bosch 15167 for the same application.

Vehicle Fitment

• Fits 2007-2018 Ford Expedition, front.
• Fits 2001 Ford Expedition, front.
• Fits 1983-2018 Ford F-150, rear outer. 8.80" ring gear; Schaeffler Seal Global Number 413 2578 100.
• Fits 1983-2018 Ford F-150, front outer. 8.80" ring gear; Schaeffler Seal Global Number 413 2578 100.
• Fits 2009-2018 Lincoln Navigator, front.
• Fits 2002 Lincoln Navigator, front.
• Fits 2003-2014 Ford E-150, rear.
• Fits 1979-2014 Ford Mustang, rear.
• Fits 1992-2011 Ford Crown Victoria, rear outer.
• Fits 1983-2011 Ford Ranger, rear.
• Fits 1981-2011 Lincoln Town Car, rear.
• Fits 1975-2011 Mercury Grand Marquis, rear.
• Fits 1991-2010 Ford Explorer, rear.
• Fits 2007-2010 Ford Explorer Sport Trac, rear.
• Fits 2001-2005 Ford Explorer Sport Trac, rear.
• Fits 2001-2010 Mazda B2300, rear outer.
• Fits 1994-2010 Mazda B4000, rear.
• Fits 1997-2010 Mercury Mountaineer, rear.
• Fits 1999-2008 Ford E-350 Super Duty, rear.
• Fits 2000-2008 Jaguar S-Type, rear.
• Fits 2006-2008 Lincoln Mark LT, front.
• Fits 2003-2008 Lincoln Navigator, rear.
• Fits 1998-2001 Lincoln Navigator, rear.
• Fits 1994-2008 Mazda B3000, rear.
• Fits 2002-2007 Saturn Vue, rear. Schaeffler Seal Global Number 413 2578 100.
• Fits 2005-2006 Chevrolet Equinox, rear. Schaeffler Seal Global Number 413 2578 100.
• Fits 2002-2006 Ford Expedition, rear.
• Fits 1997-2000 Ford Expedition, rear.
• Fits 2000-2006 Lincoln LS, rear.
• Fits 2001-2006 Mazda Tribute, rear outer.
• Fits 2006 Pontiac Torrent, rear. Schaeffler Seal Global Number 413 2578 100.
• Fits 2003-2005 Ford E-150 Club Wagon, rear.
• Fits 2002-2005 Ford Thunderbird, rear.
• Fits 1979-1997 Ford Thunderbird, rear.
• Fits 2003-2005 Lincoln Aviator, rear.
• Fits 2004 Ford F-150 Heritage, rear.
• Fits 1995-2004 Ford Grand Marquis, rear.
• Fits 2003-2004 Mercury Marauder, rear.
• Fits 1970 Mercury Marauder, rear.
• Fits 2001-2003 Ford Explorer Sport, rear.
• Fits 1983-2002 Ford E-150 Econoline, rear.
• Fits 1983-2002 Ford E-150 Econoline Club Wagon, rear.
• Fits 1998-2001 Mazda B2500, rear.
• Fits 1997-1999 Ford F-250, front.
• Fits 1993-1998 Lincoln Mark VIII, rear.
• Fits 1986-1997 Ford Aerostar, rear.
• Fits 1994-1997 Mazda B2300, rear.
• Fits 1980-1997 Mercury Cougar, rear.
• Fits 1983-1996 Ford Bronco, rear.
• Fits 1991-1994 Mazda Navajo, rear.
• Fits 1991-1993 Mazda B2600, rear.
• Fits 1984-1992 Lincoln Mark VII, rear.
• Fits 1987-1991 Ford LTD Crown Victoria, rear.
• Fits 1987-1991 Mercury Colony Park, rear.
• Fits 1971-1974 Mercury Colony Park, rear.
• Fits 1984-1990 Ford Bronco II, rear.
• Fits 1984-1990 Ford F-250, rear.
• Fits 1983-1989 Ford E-250 Econoline, rear.
• Fits 1983-1989 Ford E-250 Econoline Club Wagon, rear.
• Fits 1982-1987 Lincoln Continental, rear.
• Fits 1980 Lincoln Continental, rear.
• Fits 1965-1986 Ford LTD, rear.
• Fits 1979-1986 Mercury Capri, rear.
• Fits 1971-1986 Mercury Marquis, rear.
• Fits 1983 Ford E-100 Econoline, rear.
• Fits 1983 Ford E-100 Econoline Club Wagon, rear.
• Fits 1983 Ford F-100, rear.
• Fits 1978-1983 Ford Fairmont, rear.
• Fits 1980-1983 Lincoln Mark VI, rear.
• Fits 1978-1983 Mercury Zephyr, rear.
• Fits 1980 Lincoln Versailles, rear.
• Fits 1980 Mercury Monarch, rear.
• Fits 1975-1978 Mercury Monarch, rear.

Common Uses

• Replacing a leaking differential pinion seal
• Addressing gear oil seepage at the axle pinion area
• Restoring sealing performance after contamination or wear
• Helping reduce dirt, dust, and moisture intrusion into driveline components
• Supporting proper lubricant retention in rear or front axle service

Installation Notes and Tips

Verify the seal dimensions, axle configuration, and position before installation. This part is used in front, rear, rear outer, and front outer applications depending on the vehicle, so match the vehicle listing and axle location exactly. Inspect the pinion surface for wear or scoring before installing the new seal, and confirm the mating surface is clean and dry.

For Ford F-150, Ford Expedition, and Lincoln Navigator applications, confirm the axle and ring gear details listed in the fitment notes where provided. Proper installation and correct alignment are important for sealing performance.

Quality Assurance

FAG sources materials and designs seals to meet vehicle manufacturer specifications, with application-specific engineering focused on sealing durability and contamination control. The SS2578 is built to the dimensional and material requirements listed above for service use in the specified driveline applications.