National 451078 Differential Pinion Seal - Rear Outer

National Differential Pinion Seal 451078 Overview

The National 451078 differential pinion seal is engineered for reliable sealing performance in Ford F-100, F-250, and F-350 models. Designed with precision dimensions and durable nitrile material, this oil seal helps maintain proper lubrication and prevent leaks in driveline applications.

• Inside diameter: 1.875 inches (47.630 mm)
• Outside diameter: 3.256 inches (82.700 mm)
• Thickness/width: 0.500 inches (12.700 mm)
• Material: Nitrile for resistance to oil and wear
• Redicoat coating for enhanced durability
• Housing bore compatibility: 3.251 inches (82.580 mm)
• Zero duplication part ensuring unique fit and quality

Technical Details and Specifications

The National 451078 differential pinion seal is part of the 450000 series and is specifically designed to fit the pinion shaft diameter of 1.875 inches (47.630 mm) commonly found in Ford F-100, F-250, and F-350 trucks. The seal’s outside diameter of 3.256 inches (82.700 mm) matches the housing bore size of approximately 3.251 inches (82.580 mm), ensuring a secure and precise fit. Constructed from nitrile material, this seal offers resistance to oil, heat, and wear, which is critical for maintaining the integrity of the differential assembly. The Redicoat treatment further enhances the seal’s longevity by providing additional protection against corrosion and abrasion.

Compatible Vehicles and Applications

This differential pinion seal is compatible with the following Ford models:

• Ford F-100
• Ford F-250
• Ford F-350

It is designed for use in driveline and axle assemblies where maintaining oil containment and preventing contamination is essential for optimal differential performance.

Common Issues Addressed by the National 451078 Seal

• Prevents oil leaks from the differential pinion shaft
• Reduces contamination ingress that can damage internal components
• Maintains proper lubrication within the differential housing
• Minimizes wear on the pinion shaft and housing bore
• Helps avoid costly differential repairs due to seal failure

Installation Notes and Tips

• Ensure the housing bore and pinion shaft are clean and free of debris before installation
• Use appropriate tools to press the seal evenly into the housing bore without distortion
• Verify the seal orientation matches the original to maintain proper sealing function
• Check shaft and bore dimensions to confirm compatibility with the 1.875 inch shaft and 3.256 inch housing bore
• Inspect the seal for damage prior to installation to avoid premature failure

Quality Assurance and Warranty

National’s 451078 differential pinion seal is manufactured to meet strict quality standards for durability and fitment. The seal is a zero duplication part, ensuring unique design and reliable performance. While specific warranty details may vary, National products typically come with a limited warranty against defects in material and workmanship, providing confidence in the product’s longevity and function.