National 710685 Drive Axle Shaft Seal - Front Outer

Drive Axle Shaft Seal for Ford Super Duty

The National 710685 drive axle shaft seal is built for front outer axle sealing on select Ford heavy-duty trucks and SUV applications. It uses nitrile material and OE-style dimensions to support a precise seal at the axle shaft and housing interface.

National has supplied sealing solutions for more than 75 years, and the 710685 reflects that focus with a design aligned to modern driveline requirements. This part cross-references Four Seasons (e.g., 35298, 55474) for the same application.

Key Features

• Nitrile construction for sealing performance in driveline service
• Part description: oil seal
• Inside diameter: 3.528 in. / 89.610 mm
• Outside diameter: 5.469 in. / 138.900 mm
• Housing bore: 5.465 in. / 138.800 mm
• Width: 0.654 in. / 16.610 mm
• OE-style dimensions for front outer axle locations
• National part number 710685

Detailed Description

National 710685 is a drive axle shaft seal designed for front outer applications on Ford F-250 Super Duty and Ford F-350 Super Duty models, including 2005-2018 trucks with OE design, 9.75 in ring gear, Spicer 60-SF axle, and Monobeam axle, plus 2019-2020 Ford F-250 Super Duty and F-350 Super Duty front outer fitment. It also fits the 2005 Ford Excursion front outer position with the same axle configuration. The seal’s nitrile material and measured dimensions help maintain a proper interface between the shaft and housing bore.

What It Helps Address

• Gear oil seepage at the front outer axle shaft seal
• Contamination entering the axle housing through a worn seal
• Fluid loss caused by hardened or damaged sealing lips
• Noise or driveline concerns related to low axle lubricant level
• Service issues from an incorrect seal size or profile

Installation Notes and Tips

Verify axle configuration, housing bore, shaft diameter, and position before installation. This seal is specified for front outer use on the listed Ford applications, so confirm the vehicle has the correct 9.75 in ring gear, Spicer 60-SF axle, and Monobeam axle where required. Clean the bore and shaft sealing surface thoroughly, and inspect for wear, scoring, or corrosion that could affect sealing performance.

Quality Assurance

National has a long history in premium sealing products and continues to develop sealing solutions for current vehicle platforms. Part number 710685 is engineered to meet the dimensional requirements of the listed driveline applications.