National 370008A Wheel Seal - Rear Inner

National 370008A Wheel Seal Overview

The National 370008A wheel seal is an oil bath seal built for driveline and axle sealing applications where consistent lubricant retention matters. It uses nitrile material and precise dimensions to support a secure seal at the housing bore and shaft interface.

National has supplied sealing solutions for more than 75 years, and this wheel seal reflects that focus on dimensional accuracy and modern vehicle service needs. It is a practical choice for axle and hub service on applications such as Ford F-100 and Ford F-250 where an oil bath seal is specified.

Key Features

• Part number: 370008A
• Wheel seal / oil bath seal for driveline and axle sealing systems
• Nitrile sealing material for dependable fluid resistance
• Outside diameter: 5.386 in. / 136.600 mm
• Housing bore: 5.372 in. / 136.450 mm
• Shaft diameter: 3.937 in. / 100.000 mm
• Width: 1.015 in. / 25.780 mm
• Installation tool reference: RD281

Detailed Description

National 370008A is a wheel seal engineered for oil bath sealing applications in axle and hub assemblies. Its nitrile construction and measured dimensions help maintain a controlled seal between the housing bore, shaft diameter, and rotating components. The seal is identified as Series 370000 and Type 11, with dimensions listed in both inch and metric units for easier verification during service.

This part cross-references Four Seasons 39380 for the same application. It is also referenced in service applications associated with Ford truck platforms, including Ford F-100 and Ford F-250, where accurate wheel seal replacement is important for maintaining axle lubrication and reducing contamination.

What It Helps Address

• Gear oil leakage at the wheel end
• Contamination entering the hub or axle assembly
• Seal wear from age, heat, or lubricant breakdown
• Noise or service issues related to inadequate axle sealing
• Repeat repairs caused by incorrect seal dimensions

Installation Notes and Tips

Verify housing bore, shaft diameter, and width before installation to confirm the seal matches the application. Use the specified installation tool RD281 when required to help seat the seal evenly and avoid distortion. Clean the sealing surfaces thoroughly and inspect the shaft and bore for scoring or wear before assembly.

For vehicle-specific service, confirm the exact axle and hub configuration on Ford F-100 and Ford F-250 applications before ordering. The part number 370008A should be matched to the measured dimensions and service specification, not only the vehicle nameplate.

Quality Assurance

National is known for sealing products backed by more than 75 years of industry experience. The 370008A wheel seal is built to dimensional specifications that support consistent service replacement in driveline and axle applications.