FAG SS2857 Differential Pinion Seal - Rear

FAG SS2857 Differential Pinion Seal

FAG SS2857 is a differential pinion seal built for rear axle applications that need reliable sealing at the pinion shaft. It uses a metal and spring seal design with nitrile sealing material to help retain gear oil and keep contamination out of the differential.

With a 2.623 in bore diameter, 2.627 in outside diameter, and 1.813 in width, this seal is specified for select Ford and Mercury rear differential applications, including classic Mustang, Pinto, Ranger, Bronco II, and LTD fitments.

Key Features

• Part number: SS2857
• Differential pinion seal for rear axle service
• Seal type: metal with spring
• Sealing material: nitrile
• Bore diameter: 2.623 in (66.624 mm)
• Outside diameter: 2.627 in (66.726 mm)
• Width: 1.813 in (46.05 mm)
• Cross-reference part numbers include Anchor 3618 and Bosch 18100

Detailed Description

FAG SS2857 is engineered for rear differential pinion locations where seal integrity is critical to axle performance. The nitrile sealing element and spring-loaded metal construction are selected to help maintain a consistent seal at the pinion area, reducing the chance of gear oil loss and limiting entry of dirt, dust, and moisture. This part number is listed for a wide range of Ford and Mercury rear axle applications, including 1965-1973 Ford Mustang, 1979-1982 Ford Mustang, 1979-1980 Ford Pinto, 1983-1984 Ford Ranger, 1984 Ford Bronco II, and 1975-1980 Ford LTD. It also appears in fitment for Mercury Capri, Bobcat, Zephyr, Monarch, Marquis, Montego, Cougar, and Villager applications. FAG SS2857 is a direct-fit style replacement for vehicles using the specified differential pinion seal dimensions and axle configurations.

What This Part Helps Address

• Gear oil leaking from the rear differential pinion area
• Contamination entering the pinion seal surface
• Moisture intrusion around the axle seal interface
• Seal wear that can lead to driveline noise or fluid loss
• Service replacement for worn rear differential pinion seals on Ford and Mercury vehicles

Installation Notes and Tips

Verify the seal dimensions and axle application before installation, especially on vehicles with multiple ring gear or axle variants. Clean the pinion bore and sealing surface thoroughly, and inspect the pinion yoke for wear or grooves that could affect sealing performance. Confirm the rear axle configuration on the vehicle before ordering, since fitment varies by model year and differential setup. This part is listed for rear position applications only.

Quality Assurance

FAG designs seals to meet vehicle manufacturer specifications and works with suppliers to maintain FAG quality standards. The brand’s wheel and axle sealing products are built to protect end components from contamination and help preserve lubricant over the service life of the bearing or differential assembly.