FAG SS6405 Differential Pinion Seal - Rear

Differential Pinion Seal for Ford Super Duty

The FAG SS6405 differential pinion seal is built for rear axle service on select Ford Super Duty trucks. It is designed with a metal shell, spring, and auxiliary lip to help maintain a stable seal at the pinion area while keeping contamination out of the driveline.

Compatible with 2011-2021 Ford F-250 Super Duty and 2011-2021 Ford F-350 Super Duty rear applications, this seal is a direct-fit service part for vehicles that require the listed dimensions and axle configurations. The FAG SS6405 is also cross-referenced to SKF 20042A for the same application.

Key Features

• Part number: SS6405
• Differential pinion seal for rear axle service
• Seal type: metal shell, spring, and auxiliary lip
• Sealing material: polyacrylate
• Bore diameter: 3.189 in. / 81.001 mm
• Seal outside diameter: 3.322 in. / 84.379 mm
• Seal width: 2.441 in. / 62.001 mm
• Fits select Ford F-250 Super Duty and Ford F-350 Super Duty rear axle applications

Detailed Description

FAG SS6405 is a differential pinion seal engineered for rear driveline sealing where precise dimensions matter. The polyacrylate sealing material and multi-lip design help maintain contact at the pinion interface, while the metal and spring construction supports consistent sealing performance in demanding axle environments. This part number is listed for 2011-2021 Ford F-250 Super Duty and Ford F-350 Super Duty rear applications, including 10.50-inch ring gear and Dana 70 axle configurations noted in the fitment data. If you are servicing a Ford F-250 Super Duty or Ford F-350 Super Duty rear differential, SS6405 provides the specified seal dimensions for the application.

Common Problems This Seal Can Address

• Gear oil seepage at the differential pinion area
• Contamination entering the rear axle housing
• Loss of lubricant around the pinion seal surface
• Seal wear from age, heat, and driveline use
• Noise or driveline concerns associated with low axle fluid levels

Installation Notes and Tips

Verify axle type, ring gear size, and seal dimensions before installation. Clean the pinion bore and sealing surface thoroughly, and inspect the pinion yoke for wear or grooves that could affect sealing. Proper installation depth and alignment are important for rear axle service on Ford Super Duty trucks. Confirm the replacement part number SS6405 against the original seal and vehicle configuration before assembly.

Quality Assurance

FAG designs seals to meet vehicle manufacturer specifications and works with suppliers to maintain its quality standards. This seal is built for demanding wheel-end and driveline sealing requirements, with materials selected to help protect components from dirt, dust, and moisture while retaining lubricant over the service life of the bearing or axle assembly.