FAG SS2870 Differential Pinion Seal - Rear or Rear Outer

Differential Pinion Seal for Ford Rear Axles

FAG SS2870 is a differential pinion seal built for rear axle applications across a wide range of Ford, Mercury, and Lincoln vehicles. It uses a metal shell, spring, and auxiliary lip design with polyacrylate sealing material to help keep gear oil contained while resisting contamination at the pinion area.

Fits 1957-1988 Ford, Mercury, and Lincoln rear axle applications, including Ford F-100, F-150, F-250, Bronco, E-100 Econoline, E-150 Econoline, E-250 Econoline, Mustang, Thunderbird, LTD, and related rear-position listings. Part number SS2870 is also a direct reference point for buyers searching by OE-style seal dimensions and application coverage.

Key Features

• Part type: differential pinion seal
• Seal type: metal, spring, and auxiliary lip
• Sealing material: polyacrylate
• Bore diameter: 3 in. / 76.2 mm
• Outside diameter: 3.005 in. / 76.327 mm
• Seal width: 1.813 in. / 46.05 mm
• Rear axle application coverage for select Ford, Mercury, and Lincoln vehicles
• FAG SS2870 for application-specific driveline sealing

Detailed Description

FAG SS2870 is engineered as a differential pinion seal for rear driveline service where the pinion shaft enters the axle housing. The metal-backed construction helps maintain seal stability, while the spring-loaded lip and auxiliary lip support sealing performance at the rotating shaft interface. Polyacrylate sealing material is used to handle the demands of axle lubrication and road exposure.

This seal is listed for a broad range of rear applications, including Ford F-100, F-150, F-250, Bronco, Mustang, Thunderbird, and E-Series Econoline models, along with select Mercury and Lincoln vehicles. If you are sourcing a rear differential pinion seal for a classic Ford truck or passenger car, SS2870 provides a dimensioned replacement option for the specified applications. This part cross-references Baldwin 18264 for the same application.

What It Helps Address

• Gear oil leaking from the differential pinion area
• Contamination entering the axle housing through the pinion seal
• Grease or lubricant loss at the rear axle sealing point
• Noise or wear concerns caused by low axle lubricant levels
• Seal replacement needs during rear differential service

Installation Notes and Tips

Confirm axle application, seal dimensions, and position before installation. Inspect the pinion yoke, shaft surface, and housing bore for wear, scoring, or corrosion, since seal performance depends on a clean and smooth sealing surface. Proper alignment during installation is important to avoid damaging the sealing lip or spring.

For best results, verify the rear axle configuration on the vehicle and compare the old seal to FAG SS2870 before assembly. This is especially important on older Ford, Mercury, and Lincoln rear axle applications where service history may vary.

Quality Assurance

FAG designs seals using high-quality materials and application-specific specifications to meet vehicle manufacturer requirements. The seal construction is selected to protect wheel-end and driveline components from dirt, dust, and moisture while helping retain lubricant over the service life of the bearing or axle assembly.