National 470774 Automatic Transmission Extension Housing Seal

Overview of National 470774 Automatic Transmission Extension Housing Seal

The National 470774 automatic transmission extension housing seal is engineered to provide reliable sealing performance for select Buick and Cadillac models. Designed with precision, this oil seal helps maintain transmission integrity by preventing fluid leaks and contamination.

• Inside diameter: 1.375 inches (34.930 mm)
• Outside diameter: 2.066 inches (52.480 mm)
• Thickness/width: 0.375 inches (9.530 mm)
• Material: Durable nitrile compound
• Redicoat coating for enhanced wear resistance
• Compatible with housing bore size 2.062 inches (52.370 mm)
• Zero duplication part ensuring unique fit and quality

Detailed Product Description and Specifications

This National automatic transmission extension housing seal, part number 470774, is manufactured from nitrile material known for its resistance to oil, heat, and wear. The seal features a 1.375-inch inside diameter and a 2.066-inch outside diameter, matching the housing bore dimensions precisely to ensure a secure fit. With a thickness of 0.375 inches, it provides a robust barrier against transmission fluid leaks. The Redicoat treatment enhances the seal’s durability by reducing friction and extending service life. This seal is part of National's 470000 series, designed specifically for automatic transmission applications requiring reliable sealing solutions.

Compatible Vehicles and Applications

This transmission extension housing seal is compatible with various Buick and Cadillac models, including:

• Buick Century
• Buick LeSabre
• Cadillac DeVille
• Cadillac Roadmaster
• Buick Skylark

It is designed to replace worn or damaged seals in these vehicles’ automatic transmission extension housings, helping maintain proper fluid containment and transmission performance.

Common Issues Addressed by National 470774 Seal

• Prevents automatic transmission fluid leaks from the extension housing
• Reduces contamination ingress that can cause transmission wear
• Eliminates noise and vibration caused by fluid loss or seal failure
• Helps maintain proper hydraulic pressure within the transmission
• Prevents premature transmission component damage due to fluid leakage

Installation Notes and Tips

• Ensure the housing bore is clean and free of debris before installation
• Use appropriate tools to avoid damaging the seal during installation
• Verify the seal orientation matches the original part for proper sealing
• Lubricate the seal lip with transmission fluid to ease installation and prevent damage
• Check for proper fit and seating after installation to avoid leaks

Quality Assurance and Warranty

National transmission seals are manufactured to meet OEM specifications, ensuring consistent quality and performance. The 470774 seal undergoes rigorous testing for dimensional accuracy and material integrity. This part is backed by National’s quality standards and includes a limited warranty against manufacturing defects, providing confidence in its durability and reliability for Buick Century, Cadillac DeVille, and other compatible models.