National 711121 Transfer Case Output Shaft Seal - Left

Overview of National Transfer Case Output Shaft Seal 711121

The National 711121 transfer case output shaft seal is engineered to provide reliable sealing performance for select Ford, Land Rover, Mercury, and Volvo vehicles. Designed with a bi-directional lip, this oil seal helps maintain proper lubrication and prevent fluid leaks in the transfer case assembly.

• Bi-directional lip design for effective sealing in both rotational directions
• Constructed from durable polyacrylate material for resistance to heat and wear
• Housing bore diameter of 2.559 inches (65.000 mm) ensures precise fit
• Outside diameter measures 2.567 inches (65.200 mm) for compatibility with specified transfer cases
• Overall width with side lip is 0.370 inches (9.400 mm) for secure installation
• Shaft diameter of 1.890 inches (48.000 mm) matches OEM specifications
• Part of the National 711100 series, known for consistent quality in sealing systems

Detailed Product Description

The National 711121 transfer case output shaft seal is designed to meet the exacting standards required for transfer case applications in vehicles such as the Ford Five Hundred, Land Rover Discovery Sport, Mercury Montego, and Volvo XC90. Its bi-directional lip design provides a reliable seal against oil leakage regardless of shaft rotation direction, which is critical for maintaining transfer case integrity and performance.

Manufactured from polyacrylate, this seal offers excellent resistance to heat, oil, and wear, extending the service life of the transfer case components. The precise dimensions, including a housing bore of 2.559 inches and an outside diameter of 2.567 inches, ensure a snug fit that prevents contamination and fluid loss. The overall width with side lip of 0.370 inches supports proper sealing pressure and installation stability.

Applications and Common Issues Addressed

• Prevents oil leaks from the transfer case output shaft
• Reduces risk of transfer case contamination by dirt and debris
• Helps maintain proper lubrication for transfer case components
• Addresses wear-related seal failures in Ford, Land Rover, Mercury, and Volvo models
• Supports transfer case performance in vehicles like the Range Rover Evoque and Volvo S60

Installation Notes and Tips

When installing the National 711121 transfer case output shaft seal, ensure the housing bore and shaft dimensions match the specified measurements for a proper fit. Clean the sealing surface thoroughly to remove any debris or old sealant. Use appropriate tools to press the seal evenly into place without damaging the lip. Verify the seal orientation to maintain the bi-directional lip’s effectiveness.

Quality Assurance and Warranty

National transfer case seals, including part number 711121, are manufactured to meet industry standards for durability and performance. The polyacrylate material and precise engineering contribute to consistent sealing reliability. While specific warranty details are not provided, National products typically adhere to quality control processes to ensure customer satisfaction and part longevity.