National 380003A Wheel Seal - Rear or Rear Inner

National 380003A Wheel Seal Overview

National 380003A is an oil bath wheel seal built for driveline and axle sealing applications that demand accurate dimensions and durable sealing performance. It uses PTFE material and is specified with a 6.322 in outside diameter, 6.309 in housing bore, and 4.765 in shaft diameter for a precise service fit.

For technicians servicing heavy-duty axle assemblies, this National wheel seal supports clean oil retention and helps keep contaminants out of the hub area. It is a direct-fit style seal for applications that call for National 380003A.

Key Features

• Wheel seal / oil bath seal for driveline and axle service
• PTFE sealing material for consistent sealing contact
• Outside diameter: 6.322 in (160.480 mm)
• Housing bore: 6.309 in (160.300 mm)
• Shaft diameter: 4.765 in (121.030 mm)
• Width: 1.132 in (28.750 mm)
• Series: 380000
• Installation tool reference: RD305

Detailed Description

National 380003A is engineered as an oil bath seal for axle and hub assemblies where stable sealing dimensions matter. The PTFE construction is selected for sealing performance in demanding driveline environments, while the listed bore, shaft, and width measurements help confirm proper application matching before installation. This part is commonly searched as a wheel seal for heavy-duty axle service, National 380003A seal, and oil bath seal replacement for compatible driveline assemblies. It cross-references SKF 47691 for the same application.

When replacing a worn seal, verify the housing bore, shaft diameter, and seal width against the original component to ensure correct seating and sealing contact. National 380003A is also relevant in searches for Ford F-Series wheel seal replacement and Chevrolet/GMC truck axle seal service where the application calls for this exact part number.

Common Problems This Seal Can Address

• Gear oil leakage at the wheel end or hub area
• Contamination entering the axle or oil bath assembly
• Seal wear from heat, age, or mileage
• Loss of proper sealing contact after hub service
• Noise or damage associated with low lubricant retention

Installation Notes and Tips

Confirm the housing bore, shaft diameter, and seal width before installation. Use the specified installation tool RD305 when the service procedure calls for it, and inspect the shaft surface for scoring or wear that could affect sealing. Clean the bore thoroughly and seat the seal evenly to avoid distortion. For fitment-based searches, this part is often referenced for Ford F-Series and Chevrolet/GMC truck axle service, but final application confirmation should always be based on the original seal dimensions and service data.

Quality Assurance

National has supplied sealing solutions for more than 75 years and continues to develop sealing components for modern vehicle service needs. National 380003A reflects that focus with application-specific dimensions and PTFE construction for driveline sealing work.