National 4764 Automatic Transmission Extension Housing Seal

Automatic Transmission Extension Housing Seal

National 4764 is an automatic transmission extension housing seal built for specific Ford, Lincoln, Mercury, and Nissan applications. It uses a polyacrylate sealing material with a counter-clockwise spiral lip design and Redicoat surface treatment for consistent sealing performance in the transmission tail housing area.

Compatible With Ford F-150, Ford E-Series vans, Lincoln Town Car, Mercury Grand Marquis, and Nissan Quest applications listed below, this seal is sized for the shaft and housing dimensions shown in the specifications. National 4764 is also cross-referenced to ATP LO-42 for the same application.

• Polyacrylate sealing material for transmission fluid sealing
• Counter-clockwise spiral lip design
• Redicoat surface treatment
• Inside diameter: 1.598 in. / 40.590 mm
• Outside diameter: 2.483 in. / 63.070 mm
• Housing bore: 2.476 in. / 62.890 mm
• Overall width with side lip: 0.783 in. / 25.400 mm
• National Series 4000 oil seal design

Detailed Product Overview

This automatic transmission extension housing seal is designed for vehicles using Ford 4R70W, 4R70E, 4R75W, 4R75E, AOD-EW, 5R55N, and 5R55W transmissions, plus Nissan Quest and Nissan Altima or Maxima applications with the Aisin 55-50SN transmission. National 4764 is engineered around the listed shaft, housing bore, and width dimensions to support a proper seal at the extension housing and reduce fluid leakage at the rear of the transmission.

National has supplied sealing solutions for more than 75 years, and this part reflects that focus on transmission sealing components. If you are servicing a Ford F-150, E-150, E-250, Crown Victoria, Town Car, or Grand Marquis, verify the transmission code and housing dimensions before installation to confirm the correct application.

What This Seal Helps Address

• Transmission fluid leaking from the extension housing area
• Wet or contaminated tail housing surfaces
• Seal wear from age, heat, and fluid exposure
• Improper sealing after transmission service
• Fitment issues when the transmission code does not match the vehicle year

Installation Notes and Tips

Confirm the transmission model, shaft diameter, and housing bore before installation. Clean the extension housing and shaft sealing surface thoroughly, and inspect for scoring or wear that could affect seal life. For Ford F-150, E-Series, Crown Victoria, and Lincoln Town Car applications, match the transmission code in the fitment notes to the vehicle exactly, since several model years use different units.

National 4764 is listed for 1993-2014 model-year coverage across the included Ford, Lincoln, Mercury, and Nissan applications. Body fitment includes Ford E-150, E-250, E-350 Super Duty, F-150, Expedition, Mustang, Thunderbird, Explorer, Crown Victoria, Lincoln Town Car, Mercury Grand Marquis, and Nissan Quest, Altima, and Maxima configurations shown in the fitment data.

Quality Assurance

National is a long-established sealing brand with a reputation built over decades in the aftermarket and OE service space. Part number 4764 is manufactured as a transmission oil seal with defined dimensional specifications and material details for application matching.