National 3604 Differential Pinion Seal - Front Outer, Rear or Rear Outer

National 3604 Differential Pinion Seal Overview

The National 3604 differential pinion seal is engineered to provide reliable sealing performance for driveline applications. Designed for select Ford, Lincoln, Mazda, and Mercury vehicles, this oil seal helps maintain proper lubrication and prevents leaks in the differential assembly.

• Inside diameter: 1.812 inches (46.020 mm)
• Outside diameter: 2.783 inches (70.690 mm)
• Flanged outside diameter: 3.150 inches (80.000 mm)
• Thickness: 0.455 inches (11.560 mm)
• Material: durable fluoro-elastomer
• Clockwise-spiral lip design for enhanced sealing
• Redicoat coating for corrosion resistance
• Compatible with housing bore of 2.777 inches (70.540 mm)

Technical Details and Design Features

The National 3604 differential pinion seal features a fluoro-elastomer construction that offers resistance to heat, oil, and wear, making it suitable for demanding automotive environments. Its clockwise-spiral lip design ensures effective sealing around the pinion shaft, reducing the risk of oil leaks. The seal’s flanged outside diameter of 3.150 inches (80 mm) provides a secure fit within the differential housing bore, which measures 2.777 inches (70.540 mm). The Redicoat finish adds an extra layer of corrosion protection, extending the service life of the seal.

Compatible Vehicles and Applications

This differential pinion seal is compatible with a wide range of Ford, Lincoln, Mazda, and Mercury models, including but not limited to the Ford F-150, Explorer, Mustang, Bronco, and Ranger, as well as Lincoln Navigator and Continental, Mazda B2300, B2500, B3000, and Mercury Cougar. The National 3604 is designed to meet the specifications required for these vehicles’ driveline and axle sealing systems.

Common Issues Addressed by the National 3604 Seal

• Prevents differential oil leaks that can cause driveline damage
• Maintains proper lubrication of the pinion shaft
• Reduces contamination ingress into the differential assembly
• Minimizes wear on differential components due to oil loss
• Helps avoid costly repairs related to seal failure

Installation Notes and Tips

When installing the National 3604 differential pinion seal, ensure the housing bore and shaft are clean and free of debris. Use appropriate tools to press the seal evenly into the housing bore without damaging the sealing lip. Verify the seal orientation matches the clockwise-spiral lip design for optimal performance. It is recommended to inspect the pinion shaft for wear or damage before installation and replace if necessary.

Quality Assurance and Warranty

National manufactures the 3604 differential pinion seal to meet industry standards for durability and performance. The fluoro-elastomer material and Redicoat corrosion protection contribute to a reliable service life. This part is backed by National’s quality assurance processes, ensuring consistent fit and function for compatible Ford, Lincoln, Mazda, and Mercury models. Warranty coverage details should be confirmed with the original equipment manufacturer or authorized distributor.