InMotion WS4278 Differential Pinion Seal - Rear Outer

Differential Pinion Seal for Ford Rear Outer Applications

The InMotion WS4278 differential pinion seal is built to help maintain a secure seal at the rear outer pinion location. Made from fluoro-elastomer, it is specified for demanding driveline service where resistance to heat, fluid exposure, and contamination matters.

Compatible With Ford F-150, Expedition, Mustang, Transit-150, Transit-250, Transit-350, Transit-350 HD, E-150, Excursion, F-250 Super Duty, F-350 Super Duty, Lincoln Navigator, Mark LT, and Blackwood applications with the listed ring gear and housing dimensions.

• Fluoro-elastomer construction for sealing performance in driveline service
• Inside diameter: 1.812 in.
• Outside diameter: 3.096 in.
• Housing bore: 3.091 in.
• Thickness: 0.485 in.
• Shaft diameter: 1.812 in.
• Rear outer differential pinion seal location

Fitment Details

• Fits 2008-2022 Ford F-150, rear outer, with 9.75in ring gear
• Fits 2000-2003 Ford F-150, rear outer, with 9.75in ring gear
• Fits 2000-2018 Ford Expedition, rear outer, with 9.75in ring gear
• Fits 2015-2018 Ford Mustang, rear outer, with 9.75in ring gear
• Fits 2015-2018 Ford Transit-150, rear outer, with 9.75in ring gear
• Fits 2015-2018 Ford Transit-250, rear outer, with 9.75in ring gear
• Fits 2015-2018 Ford Transit-350, rear outer, with 9.75in ring gear
• Fits 2015-2018 Ford Transit-350 HD, rear outer, with 9.75in ring gear
• Fits 2000-2018 Lincoln Navigator, rear outer, with 9.75in ring gear
• Fits 2003-2011 Ford E-150, rear outer, with 9.75in ring gear
• Fits 1999-2010 Ford F-250 Super Duty, rear outer, with 10.5in ring gear
• Fits 1999-2010 Ford F-350 Super Duty, rear outer, with 10.5in ring gear
• Fits 2006-2008 Lincoln Mark LT, rear outer, with 9.75in ring gear
• Fits 2004-2007 Ford F-150, rear outer, with 10.25in ring gear
• Fits 2003-2005 Ford E-150 Club Wagon, rear outer, with 9.75in ring gear
• Fits 2000-2005 Ford Excursion, rear outer, with 10.5in ring gear
• Fits 2004 Ford F-150 Heritage, rear outer, with 9.75in ring gear
• Fits 2000-2002 Ford E-150 Econoline, rear outer, with 9.75in ring gear
• Fits 2000-2002 Ford E-150 Econoline Club Wagon, rear outer, with 9.75in ring gear
• Fits 2002 Lincoln Blackwood, rear outer, with 9.75in ring gear
• Fits 1999 Ford E-150 Econoline, rear outer, 3.09in outside diameter
• Fits 1999 Ford E-150 Econoline Club Wagon, rear outer, 3.09in outside diameter
• Fits 1999 Ford Expedition, rear outer, 3.09in outside diameter
• Fits 1999 Ford F-150, rear outer, 3.09in outside diameter
• Fits 1985-1999 Ford F-250, rear outer, with 10.25in ring gear
• Fits 1999 Lincoln Navigator, rear outer, 3.09in outside diameter
• Fits 1985-1997 Ford F-350, rear outer, with 10.25in ring gear

What This Seal Helps Address

• Differential fluid seepage at the pinion area
• Contamination from dirt, debris, and moisture entering the housing
• Wear related to a compromised rear outer pinion seal
• Service needs on Ford and Lincoln rear differential assemblies

Installation Notes

Verify ring gear size, housing bore, shaft diameter, and seal dimensions before installation. Clean the sealing surface thoroughly and inspect the pinion area for wear or scoring that could affect seal life. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Quality Assurance

InMotion WS4278 is manufactured with fluoro-elastomer material selected for sealing durability in differential service. The part is engineered for precise dimensional fit in the listed Ford and Lincoln rear outer applications.