National 4918 Automatic Transmission Torque Converter Seal - Front

Overview of National 4918 Automatic Transmission Torque Converter Seal

The National 4918 automatic transmission torque converter seal is engineered to provide reliable sealing performance for a range of vehicles including Buick, Chevrolet, Oldsmobile, Pontiac, Saturn, and Volvo models. Designed with precision dimensions and durable polyacrylate material, this seal helps maintain transmission fluid integrity and prevents leaks.

• Inside diameter options: 1.787 inch (45.390 mm)
• Outside diameter: 3.238 inch (82.250 mm)
• Flanged outside diameter: 3.450 inch (87.630 mm)
• Thickness: 0.335 inch (8.510 mm)
• Sealing material: Polyacrylate with clockwise-spiral lip design
• Redicoat surface treatment for enhanced durability
• Compatible with housing bore diameter of 3.228 inch (82.000 mm)

Technical Details and Material Specifications

The National 4918 seal is constructed from polyacrylate, a material known for its resistance to heat and transmission fluids, ensuring long-lasting performance in automatic transmissions. The clockwise-spiral lip design improves sealing efficiency by maintaining consistent contact with the shaft, reducing the risk of fluid leakage. The seal features a flanged outside diameter of 3.450 inches (87.630 mm) to provide a secure fit within the transmission housing bore of 3.228 inches (82.000 mm). Additionally, the Redicoat treatment enhances corrosion resistance and extends the service life of the seal.

Compatible Vehicles and Applications

This torque converter seal is compatible with a variety of vehicle makes and models, including Buick Allure, Century, LaCrosse, Lucerne, and Regal; Chevrolet Impala, Malibu, Monte Carlo, and Silverado; Oldsmobile Aurora, LSS, and Silhouette; Pontiac G6, Grand Prix, and Bonneville; Saturn Relay and Vue; as well as Volvo S80 and XC90. The National 4918 seal is designed to meet the specifications required for these vehicles’ automatic transmission systems, ensuring proper fit and function.

Common Issues Addressed by the National 4918 Seal

• Prevents automatic transmission fluid leaks around the torque converter
• Reduces contamination of transmission fluid by external debris
• Maintains proper hydraulic pressure within the transmission system
• Minimizes premature wear of transmission components due to fluid loss
• Helps avoid costly transmission repairs caused by seal failure

Installation Notes and Tips

When installing the National 4918 torque converter seal, ensure the transmission housing bore and shaft are clean and free of debris. Use appropriate tools to avoid damaging the seal during installation. Verify the seal’s orientation, with the clockwise-spiral lip facing the correct direction to maintain effective sealing. Lubricate the seal lip with transmission fluid before installation to reduce initial wear. Proper installation will help maintain transmission performance and prevent leaks.

Quality Assurance and Warranty Information

National transmission seals are manufactured to meet industry standards for durability and performance. The 4918 seal includes a Redicoat surface treatment to enhance corrosion resistance and longevity. While specific warranty details may vary, National products typically come with a limited warranty against defects in material and workmanship. Refer to the product documentation for exact warranty terms.