National 100165 Automatic Transmission Output Shaft Seal - Left

Automatic Transmission Output Shaft Seal

National 100165 is an automatic transmission output shaft seal built for metric applications with a 35.000 mm shaft size and a 57.300 mm outside diameter. It uses nitrile material and Redicoat protection to help maintain a reliable seal at the transmission housing.

Fits 1997-2011 Buick, Chevrolet, Oldsmobile, Pontiac, Saturn, and Volvo applications listed below, including left-side positions on vehicles such as the Buick Lucerne, Chevrolet Impala, and Pontiac Grand Prix. National 100165 is a direct-fit sealing component for 4T65-E and 4T65-EG transmission applications where specified.

Key Features

• Part number: National 100165
• Automatic transmission output shaft seal / oil seal
• Metric dimensions for accurate housing and shaft fit
• Nitrile sealing material for transmission fluid resistance
• Redicoat surface treatment
• Inside diameter: 35.000 mm (1.378 in.)
• Outside diameter: 57.300 mm (2.246 in.)
• Width: 15.270 mm (0.601 in.)
• Flanged outside diameter: 64.000 mm (2.520 in.)
• Housing bore: 57.000 mm (2.244 in.)

Detailed Description

National has supplied sealing solutions for more than 75 years, and the 100165 output shaft seal reflects that focus on transmission sealing accuracy. This seal is designed around metric dimensions and is listed with Type 74 construction, making it a practical replacement for vehicles using the GM 4T65-E and 4T65-EG transmission families where noted in the fitment data. It cross-references BBB Industries 13735 for the same application.

Vehicle coverage includes Buick Lucerne, LaCrosse, Allure, Century, LeSabre, Park Avenue, Regal, Riviera, and Rendezvous; Chevrolet Impala, Malibu, Monte Carlo, Lumina, and Uplander; Pontiac Grand Prix, Bonneville, Aztek, Montana, and Trans Sport; plus Oldsmobile Aurora, Intrigue, 88, LSS, Regency, and Silhouette. Volvo S80 and XC90 listings are also included where equipped with the specified transmission.

What This Seal Helps Address

• Transmission fluid seepage at the output shaft area
• Leakage around the transmission housing bore
• Seal wear from age, heat, and fluid exposure
• Loss of sealing performance on 4T65-E / 4T65-EG applications
• Drips or residue near the left-side transmission output shaft

Installation Notes and Tips

Verify shaft diameter, housing bore, and transmission family before installation. Clean the sealing surface and inspect the shaft for grooves or damage that could affect sealing. Confirm the vehicle listing by year, make, model, and left-side application before replacing the old seal. For best results, install the seal squarely to avoid distortion during seating.

Quality Assurance

National is known for premium sealing solutions and ongoing design support for modern vehicle applications. Part number 100165 is built to meet the dimensional requirements shown above and is backed by National’s long-standing sealing product expertise.