National 711143 Transfer Case Output Shaft Seal - Rear

Transfer Case Output Shaft Seal Overview

National 711143 is a premium transfer case output shaft seal built for sealing performance in demanding driveline service. It uses FKM sealing material and a bi-directional helix design to help maintain a consistent seal under operating conditions.

Compatible With rear transfer case applications on Ford and Lincoln trucks and SUVs, including Ford F-150, Ford Expedition, and Lincoln Navigator. The National 711143 seal is sized with a 1.80-inch inside diameter, 2.760-inch outside diameter, and 1.220-inch thickness for the specified housing and shaft dimensions.

Key Features

• FKM sealing material for resistance to heat and fluid exposure
• Bi-directional helix design for sealing performance in either rotation direction
• Triple-rim shape for added sealing contact
• Premium grade construction for transfer case service
• Designed for rear transfer case output shaft applications

Detailed Description

This transfer case output shaft seal is engineered for rear driveline sealing where the output shaft passes through the transfer case housing. National 711143 is a direct-fit sealing component for 2015-2020 Ford F-150 rear applications, 2018-2021 Ford Expedition rear applications, and 2018-2021 Lincoln Navigator rear applications. The FKM material and triple-rim profile support reliable sealing in modern driveline systems, while the listed shaft and housing dimensions help confirm proper fitment before installation. This part cross-references Ford FL3Z7B215B for the same application.

What It Is Used For

• Stopping transfer case fluid seepage at the output shaft
• Replacing a worn or hardened seal
• Addressing leaks caused by heat-aged sealing material
• Restoring proper sealing at the rear transfer case outlet

Installation Notes and Tips

Verify shaft diameter, housing bore, and seal dimensions before installation. Clean the sealing surface and inspect the shaft for wear, scoring, or contamination that could affect seal life. Confirm the application by vehicle year, make, model, and rear position before ordering.

Quality Assurance

National has supplied sealing solutions for more than 75 years and continues to develop sealing products for current vehicle platforms. Part number 711143 reflects that focus on application-specific sealing design and material selection.