National 4950 Automatic Transmission Torque Converter Seal - Front

National 4950 Automatic Transmission Torque Converter Seal Overview

The National 4950 automatic transmission torque converter seal is engineered to provide reliable sealing performance for a wide range of GM and related vehicles. Designed with durable polyacrylate material and a clockwise-spiral lip design, this seal helps maintain transmission fluid integrity and prevent leaks in demanding driving conditions.

• Inside diameter: 1.748 inches (44.410 mm)
• Outside diameter: 2.627 inches (66.720 mm)
• Flanged outside diameter: 2.865 inches (72.770 mm)
• Thickness: 0.330 inches (8.380 mm)
• Sealing material: Polyacrylate with Redicoat coating
• Helix type: Clockwise-spiral lip design for enhanced sealing
• Compatible with housing bore diameter of 2.619 inches (66.535 mm)

Durable Construction and Design Features

The National 4950 seal is constructed from polyacrylate, a material known for its resistance to heat, wear, and transmission fluids. The clockwise-spiral lip design improves sealing efficiency by directing fluid away from the shaft, reducing the risk of leaks. The Redicoat treatment adds an extra layer of corrosion resistance, extending the service life of the seal. With precise dimensions including a 1.748-inch inside diameter and a 2.627-inch outside diameter, this seal fits securely in the transmission housing bore, ensuring a tight and reliable fit.

Compatible Vehicles and Applications

This automatic transmission torque converter seal is compatible with a broad range of vehicles from Buick, Cadillac, Chevrolet, GMC, Hummer, Isuzu, Oldsmobile, Pontiac, and Saab. It fits models such as the Chevrolet Silverado 1500, GMC Sierra 1500, Cadillac Escalade, Buick LeSabre, Pontiac Grand Prix, and many others. The National 4950 is suitable for use in transmissions requiring a type 88 seal with the 4000 series specification.

Common Issues Addressed by the National 4950 Seal

• Prevents transmission fluid leaks around the torque converter shaft
• Reduces contamination ingress into the transmission system
• Minimizes wear on transmission components by maintaining proper lubrication
• Helps maintain hydraulic pressure for smooth transmission operation
• Protects against premature seal failure due to heat and fluid exposure

Installation Notes and Tips

• Ensure the transmission housing bore and shaft are clean and free of debris before installation
• Use appropriate tools to avoid damaging the seal during installation
• Verify the seal orientation matches the clockwise-spiral lip design for optimal sealing
• Check for proper fitment with the 1.748-inch shaft diameter and 2.619-inch housing bore
• Consult vehicle service manual for torque specifications and installation procedures

Quality Assurance and Warranty

National transmission seals are manufactured to meet industry standards for durability and performance. The 4950 seal includes a Redicoat corrosion-resistant coating to enhance longevity. While specific warranty details may vary, National products typically come with a limited warranty against defects in material and workmanship, ensuring confidence in the product's reliability.