FAG SS2599 Differential Pinion Seal - Front

FAG SS2599 Differential Pinion Seal

The FAG SS2599 differential pinion seal is built with a metal seal type and Viton sealing material for dependable sealing performance in the driveline. With a 3.16 in bore diameter, 3.165 in outside diameter, and 1.552 in width, this seal is sized for specific axle applications where accurate fit and contamination control matter.

Key Features

• Part number SS2599 for differential pinion seal applications
• Metal seal type with Viton sealing material
• Bore diameter: 3.16 in (80.264 mm)
• Seal outside diameter: 3.165 in (80.391 mm)
• Seal width: 1.552 in (39.421 mm)
• Designed for front axle fitment on select Ford trucks and SUVs

Product Details

FAG SS2599 is a differential pinion seal engineered for axle sealing applications that require precise dimensions and durable sealing materials. The metal construction supports stable sealing performance, while Viton is selected for its resistance characteristics in demanding driveline environments. This seal is listed for 2001-2008 Ford F-350 Super Duty, front; 2000-2005 Ford Excursion, front; and 1999-2000 Ford F-350 Super Duty, front with Spicer 50 axle notes. The SS2599 part number is also referenced under related OE and aftermarket numbering for the same application.

This part cross-references Bosch 15503 for the same application.

What It Helps Address

• Gear oil leakage at the differential pinion area
• Contamination from dirt, dust, and moisture entering the axle assembly
• Loss of lubricant that can affect driveline component protection
• Seal wear caused by age, heat, and road exposure
• Fitment issues when replacing a worn front differential pinion seal on Ford F-350 Super Duty or Ford Excursion applications

Installation Notes and Tips

Verify axle configuration and seal dimensions before installation, especially on 1999-2000 Ford F-350 Super Duty models with Spicer 50 axle notes. Inspect the pinion yoke and sealing surface for wear, scoring, or corrosion before installing the new seal. Proper alignment and careful seating are important to help the seal perform as intended. Confirm the application by year, make, model, and front position before ordering.

Quality Assurance

FAG sources sealing components to meet vehicle manufacturer specifications and works with suppliers to maintain its quality standards. The SS2599 is built for demanding wheel-end and driveline sealing requirements, with materials selected to help protect components from contamination and lubricant loss over the service life of the bearing or axle assembly.