National 710709 Automatic Transmission Output Shaft Seal - Left

Automatic Transmission Output Shaft Seal for Select Vehicles

National 710709 is an automatic transmission output shaft seal built for select Ford, Chevrolet, Buick, GMC, Lincoln, and related applications. It uses an ethylene-acrylic sealing material and a bi-directional lip design to help maintain a consistent seal at the transmission output shaft.

With metric dimensions and OE-style sizing, this seal is specified for left-position applications across a wide range of vehicles, including Chevrolet Malibu, Ford Fusion, and Buick Encore models.

Key Features

• Automatic transmission output shaft seal
• National part number 710709
• Ethylene-acrylic material for sealing performance
• Bi-directional lip design
• Metric dimensions: 36.0 mm shaft diameter, 61.2 mm outside diameter, 10.0 mm width
• Flanged outside diameter: 67.0 mm
• Housing bore: 61.0 mm
• Part description: oil seal

Detailed Description

National 710709 is engineered as a transmission sealing component for the output shaft area, where stable sealing is critical to keeping transmission fluid contained. The seal’s 36.0 mm inside diameter, 61.2 mm outside diameter, and 10.0 mm width provide the dimensional fit needed for listed applications, while the bi-directional lip design supports sealing performance in either rotational direction. National has supplied premium sealing solutions for more than 75 years, and this part reflects that focus on transmission and drivetrain sealing accuracy.

This part cross-references Timken SL260137 and Bosch 13749 for the same application. It is a direct-fit style option for vehicles such as Chevrolet Cruze, Ford Escape, and Lincoln MKZ when the listed transmission and position match.

What It Is Used For

• Transmission fluid leakage at the output shaft seal area
• Visible seepage around the transmission housing bore
• Seal wear from age, heat, or fluid exposure
• Service replacement during transmission repair or rebuild
• Maintaining proper sealing at the left-side output shaft location

Installation Notes and Tips

Verify shaft diameter, housing bore, and width before installation to confirm the seal matches the transmission specification. Clean the sealing surface thoroughly and inspect the shaft for wear, scoring, or contamination that could affect seal life. Confirm left-position fitment and transmission code details on vehicles such as Ford Explorer, Chevrolet Equinox, and Buick LaCrosse before installation.

Quality Assurance

National is known for sealing products backed by decades of engineering experience in the automotive aftermarket. Part number 710709 is built to meet the dimensional and material requirements of the listed applications, including 2008-2019 Chevrolet Malibu, 2010-2019 Chevrolet Equinox, and 2016-2019 Ford Fusion fitments.