National 710668 Transfer Case Output Shaft Seal - Front

Transfer Case Output Shaft Seal for 4WD Applications

National 710668 is a metric transfer case output shaft seal built for front-position applications that use New Process 136C, 236C, or 246 transfer cases. It is engineered with a fluoro-elastomer sealing material and a bi-directional lip design to help maintain a tight seal at the output shaft.

Use this seal when servicing transfer case leaks on vehicles such as the Chevrolet Silverado 1500, GMC Sierra 1500, and Dodge Ram 1500 with the correct transfer case configuration. The National 710668 part number is also referenced by OE and aftermarket cross numbers for the same application.

Key Features

• Transfer case output shaft seal for front-position service
• Fluoro-elastomer sealing material for fluid resistance and durability
• Bi-directional lip design for sealing performance in rotating applications
• Metric dimensions for accurate housing and shaft fitment
• Part number 710668 from National’s 710600 series
• Cross-reference: Four Seasons 13712

Detailed Description

National 710668 is an oil seal designed for transfer case output shaft sealing in a wide range of 4WD trucks and SUVs. Key dimensions include a 1.376-inch inside diameter, 2.567-inch outside diameter, and 0.398-inch width, with a 2.559-inch housing bore. The seal uses fluoro-elastomer material and a bi-directional lip design to support sealing at the shaft interface under transfer case operating conditions. This part number 710668 is commonly used in front transfer case positions on applications such as Chevrolet Tahoe, GMC Yukon, and Chevrolet Silverado 1500 models with the specified New Process transfer case setups.

National has supplied sealing products for decades and applies that experience to modern driveline service parts. The 710668 seal is built to match metric specifications and is listed for multiple GM and Dodge 4WD applications, including Chevrolet Avalanche, GMC Yukon XL, and Dodge Ram 1500 with the proper transfer case configuration.

What This Seal Helps Address

• Transfer case fluid seepage at the output shaft
• Oil leakage around the front transfer case seal area
• Wear-related sealing loss from shaft rotation
• Service replacement for damaged or hardened seal material
• Leak repair on 4WD trucks and SUVs with New Process transfer cases

Installation Notes and Tips

Verify transfer case type, shaft size, and housing bore before installation. This seal is listed for front-position use on vehicles with New Process 136C, 236C, and 246 transfer cases, so confirm the exact drivetrain configuration before ordering. Clean the bore and shaft surface thoroughly, and inspect the shaft for grooves or wear that could affect sealing performance. Proper alignment during installation helps prevent lip damage.

Quality Assurance

National is a long-established sealing brand with more than 75 years in the industry, and its design team develops sealing solutions for current vehicle service needs. Part number 710668 is manufactured to metric specifications for accurate replacement service.