National 710948 Automatic Transmission Extension Housing Seal

Automatic Transmission Extension Housing Seal

National 710948 is an automatic transmission extension housing seal built for metric applications that require a precise shaft and housing interface. It uses PTFE material and a counter-clockwise spiral lip design to support sealing performance in Ford Super Duty truck and van applications.

Key Features

• Part number: 710948
• Automatic transmission extension housing seal / oil seal
• PTFE sealing material
• Counter-clockwise spiral lip design
• Metric dimensions for accurate fitment
• Inside diameter: 2.460 in. / 62.500 mm
• Outside diameter: 3.551 in. / 90.200 mm
• Thickness: 0.472 in. / 12.000 mm
• Housing bore: 3.543 in. / 90.000 mm
• Flanged outside diameter: 3.839 in. / 97.500 mm

Detailed Description

National 710948 is part of the 710900 series and is engineered as a transmission extension housing oil seal for metric housings and shafts. The PTFE construction and spiral lip profile are specified for controlled sealing at the extension housing interface, while the listed dimensions help confirm proper match-up during service. This part cross-references SKF 24230A and Timken SL260135 for the same application. It fits 2011-2019 Ford F-250 Super Duty, 2011-2019 Ford F-350 Super Duty, and 2016-2019 Ford E-350 Super Duty, making it a direct search match for Ford Super Duty transmission seal replacement needs. National has supplied sealing solutions for decades and continues to apply current design standards to modern vehicle service parts.

Common Uses

• Transmission fluid leakage at the extension housing
• Worn or hardened rear transmission seal surfaces
• Service replacement during transmission repair
• Seal replacement after driveline or output shaft service
• Restoring a proper seal between the housing and shaft

Installation Notes

Verify shaft diameter, housing bore, and seal width before installation. Clean the housing bore and sealing surface thoroughly, and inspect the output shaft for wear, scoring, or corrosion that could affect sealing. Confirm the counter-clockwise spiral lip orientation matches the application before pressing the seal into place. For Ford F-250 Super Duty, Ford F-350 Super Duty, and Ford E-350 Super Duty service, match the seal dimensions to the transmission case and extension housing specification.

Quality Assurance

National is a long-established sealing brand with more than 75 years in the industry, and this part reflects that focus on precision sealing components for automotive service. The design is based on current vehicle requirements and metric dimensional standards used in modern transmission applications.