National 710426 Manual Transmission Output Shaft Seal

Manual Transmission Output Shaft Seal for Tremec T56 and T5WC

The National 710426 manual transmission output shaft seal is built for specific Ford Mustang and Pontiac GTO applications that use Tremec or Borg-Warner manual transmissions. It is a direct-fit sealing component for the transmission output shaft area, helping maintain proper fluid control at the rear of the transmission.

Key Features

• Nitrile seal material for transmission sealing applications
• Triple lip design for added sealing contact
• Bi-directional lip design
• Inside diameter: 1.500 in. / 38.100 mm
• Outside diameter: 2.385 in. / 60.58 mm
• Thickness: 0.433 in. / 11.000 mm
• Housing bore: 2.377 in. / 60.38 mm
• Overall width with side lip: 1.043 in. / 26.500 mm
• National 710426 / Series 710400

Detailed Description

National 710426 is an oil seal for manual transmission output shaft service, engineered around the listed shaft and housing dimensions for accurate sealing performance. National has supplied sealing solutions for more than 75 years, and this seal reflects that focus with a nitrile construction, triple lip profile, and bi-directional lip design for use in manual transmission output shaft locations. It is a strong match for 2003-2004 Ford Mustang with Tremec T56 Transmission, 1998-2004 Ford Mustang with Tremec T5WC Transmission, 1994-1997 Ford Mustang with Borg-Warner T5WC Transmission, and 2004-2006 Pontiac GTO with Tremec T56 Transmission. This part cross-references SKF 14569 for the same application.

Vehicle Fitment

• Fits 2004-2006 Pontiac GTO, N/A, with Tremec T56 Transmission
• Fits 2003-2004 Ford Mustang, N/A, with Tremec T56 Transmission
• Fits 1998-2004 Ford Mustang, N/A, with Tremec T5WC Transmission
• Fits 1994-1997 Ford Mustang, N/A, with Borg-Warner T5WC Transmission

Common Problems This Seal Can Address

• Transmission fluid seepage at the output shaft area
• Oil residue around the rear of the manual transmission
• Seal wear from age, heat, and drivetrain movement
• Leak concerns after transmission service or rebuild
• Loss of sealing integrity at the housing bore interface

Installation Notes and Tips

Confirm the transmission type before ordering, since this National 710426 seal is listed for specific Tremec T56, Tremec T5WC, and Borg-Warner T5WC applications. Inspect the shaft surface and housing bore for wear, scoring, or contamination before installation, and verify the seal dimensions against the original part. Proper alignment during installation helps protect the sealing lip and supports a clean fit in the housing bore.

Quality Assurance

National is known for sealing products backed by decades of engineering and application coverage. The 710426 is part of the 710400 series and is built to the dimensional and material specifications listed for the application.