National 4934 Automatic Transmission Extension Housing Seal

Overview of National 4934 Automatic Transmission Extension Housing Seal

The National 4934 automatic transmission extension housing seal is engineered to provide reliable sealing performance for a range of GM and related vehicles. Designed with durable polyacrylate material and a counter-clockwise spiral lip, this oil seal helps maintain transmission fluid integrity and prevent leaks in demanding automotive applications.

• Inside diameter: 1.503 inches (38.18 mm)
• Outside diameter: 2.379 inches (60.43 mm)
• Flanged outside diameter: 2.723 inches (69.164 mm)
• Thickness: 0.374 inches (9.5 mm)
• Material: Polyacrylate with Redicoat coating
• Helix type: Counter-clockwise spiral lip design
• Overall width with side lip: 1.299 inches (33 mm)
• Housing bore diameter: 2.374 inches (60.3 mm)

Technical Details and Material Specifications

This National 4934 transmission extension housing seal is constructed from polyacrylate, a material known for its resistance to heat, oil, and wear. The seal features a counter-clockwise spiral lip design that enhances sealing efficiency by maintaining consistent contact with the shaft, reducing the risk of fluid leakage. The Redicoat treatment adds an extra layer of protection against corrosion and wear, extending the service life of the seal. With precise dimensions including a 1.503-inch inside diameter and a 2.379-inch outside diameter, this seal fits securely within the transmission housing bore of 2.374 inches.

Compatible Vehicles and Applications

This automatic transmission extension housing seal is compatible with a wide range of General Motors and related vehicles, including Buick, Cadillac, Chevrolet, GMC, Hummer, Isuzu, Oldsmobile, Pontiac, and Saab models. It is suitable for use in vehicles such as the Chevrolet Silverado 1500, GMC Sierra 1500, Cadillac Escalade, Hummer H2, and Isuzu Ascender, among others. The part number 4934 ensures precise fitment for models including the Chevrolet Avalanche, Suburban 1500, Trailblazer, and Pontiac GTO.

Common Issues Addressed by the National 4934 Seal

• Prevents automatic transmission fluid leaks at the extension housing
• Reduces contamination ingress into the transmission system
• Minimizes wear on transmission shafts by maintaining proper lubrication
• Helps maintain consistent hydraulic pressure within the transmission
• Protects against premature seal failure due to heat and chemical exposure

Installation Notes and Tips

When installing the National 4934 transmission extension housing seal, ensure the housing bore and shaft surfaces are clean and free of debris. Use appropriate tools to press the seal evenly into place without damaging the sealing lip. Verify the orientation of the counter-clockwise spiral lip to match the shaft rotation direction. Lubricate the seal lip lightly with transmission fluid before installation to reduce initial wear. Proper installation will help maintain the seal’s integrity and extend transmission service life.

Quality Assurance and Warranty Information

National manufactures the 4934 seal to meet stringent quality standards for durability and performance in automotive transmission applications. The polyacrylate material and Redicoat coating contribute to long-lasting service under normal operating conditions. This product is part of National’s 4000 series, known for consistent manufacturing quality. Warranty coverage details should be confirmed with the original equipment manufacturer or distributor.