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National 451078 Differential Pinion Seal - Rear Outer
National 451078 Differential Pinion Seal
National 451078 is a differential pinion seal built for rear axle sealing service on select Ford trucks. It uses nitrile material and Redi-Coat treatment to support a reliable seal at the pinion shaft, helping maintain proper lubricant retention in the differential housing.
Key Features
- Part number: 451078
- Differential pinion seal / oil seal for driveline sealing service
- Nitrile construction for sealing performance
- Redi-Coat: Yes
- Inside diameter: 1.875 in. / 47.630 mm
- Outside diameter: 3.256 in. / 82.700 mm
- Thickness: 0.500 in. / 12.700 mm
- Housing bore: 3.251 in. / 82.580 mm
- Zero duplication part
Detailed Description
National 451078 is a rear differential pinion seal for vehicles using a 1.875-inch shaft and an 82.700 mm outside diameter seal profile. It is specified as a Type 45 oil seal in the 450000 series and is sized for a housing bore of 3.251 inches. This seal is used in the rear outer position on 1953-1955 Ford F-100, 1953-1955 Ford F-250, and 1953-1955 Ford F-350 applications with the Rockwell A150 axle. This part cross-references Dorman - HELP 47280 for the same application.
What This Seal Helps Address
- Differential gear oil leakage at the pinion area
- Contamination around the rear axle pinion shaft
- Seal wear from age, heat, and lubricant exposure
- Loss of lubricant retention in the rear differential
- Service replacement needs on Ford F-100, Ford F-250, and Ford F-350 rear outer pinion locations
Installation Notes and Tips
Verify shaft diameter, housing bore, and seal orientation before installation. Clean the sealing surface and inspect the pinion yoke or shaft for wear, scoring, or corrosion that could affect sealing performance. Confirm the application is the rear outer position with the Rockwell A150 axle before ordering or installing National 451078.
Quality Assurance
National has supplied sealing solutions for more than 75 years and continues to develop seal designs for modern vehicle service needs. National 451078 is built as a precision-fit differential pinion seal for the listed Ford truck applications.
| Brand | National |
|---|---|
| Part Number | 451078 |
| Footnote | Zero Duplication Part |
| Housing Bore (Inch) | 3.251 |
| Housing Bore (MM) | 82.580 |
| Inside Diameter | 1.875 |
| Inside Diameter | 47.630 |
| Material | Nitrile |
| Outside Diameter | 3.256 |
| Outside Diameter | 82.700 |
| Outside Diameter (Inch) | 3.256 |
| Outside Diameter (mm) | 82.700 |
| Part Description | Oil Seal |
| Redicoat | Yes |
| Series | 450000 |
| Shaft (Inch) | 1.875 |
| Shaft (MM) | 47.630 |
| Thickness | 0.500 |
| Thickness | 12.700 |
| Type | 45 |
| Unit of Dimension | Inch |
| Width (Inch) | 0.500 |
| Width (mm) | 12.700 |
This part fits 9 vehicles. Search below:
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| 1955 | Ford | F-100 | Rear Outer | with Rockwell A150 Axle |
| 1955 | Ford | F-250 | Rear Outer | with Rockwell A150 Axle |
| 1955 | Ford | F-350 | Rear Outer | with Rockwell A150 Axle |
| 1954 | Ford | F-100 | Rear Outer | with Rockwell A150 Axle |
| 1954 | Ford | F-250 | Rear Outer | with Rockwell A150 Axle |
| 1954 | Ford | F-350 | Rear Outer | with Rockwell A150 Axle |
| 1953 | Ford | F-100 | Rear Outer | with Rockwell A150 Axle |
| 1953 | Ford | F-250 | Rear Outer | with Rockwell A150 Axle |
| 1953 | Ford | F-350 | Rear Outer | with Rockwell A150 Axle |
* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
This part directly replaces or is cross-referenced with the following part numbers:
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.