National 4901 Manual Transmission Output Shaft Seal - Left or Right

Reliable Manual Transmission Output Shaft Seal for Acura and Honda

The National 4901 Manual Transmission Output Shaft Seal is engineered to provide a precise fit and durable sealing performance for select Acura, Honda, and Isuzu models. Designed with a bi-directional lip and polyacrylate material, this seal helps maintain transmission integrity and prevent fluid leaks.

• Inside diameter: 1.378 inches (35.000 mm)
• Outside diameter: 2.452 inches (62.280 mm)
• Thickness: 0.315 inches (8.000 mm)
• Sealing material: Polyacrylate for enhanced durability
• Bi-directional lip design for effective sealing under varying conditions
• Compatible housing bore: 2.441 inches (62.000 mm)
• Overall width with side lip: 0.453 inches (11.500 mm)

Detailed Description of National 4901 Transmission Seal

This National 4901 output shaft seal is part of the 4000 series, designed specifically for manual transmissions in vehicles such as the Acura Integra, Honda Civic, Civic del Sol, CRX, EL, Odyssey, and Isuzu Oasis. Constructed from polyacrylate, the seal offers resistance to heat and transmission fluids, ensuring long-lasting performance. The bi-directional lip design provides a secure seal around the 1.378-inch (35 mm) shaft, preventing oil leaks and contamination. Its precise dimensions, including a 2.452-inch (62.280 mm) outside diameter and 0.315-inch (8 mm) thickness, ensure a proper fit within the transmission housing bore of 2.441 inches (62 mm).

Applications and Common Issues Addressed

• Prevents manual transmission fluid leaks on Acura and Honda models
• Protects transmission internals from dirt and debris contamination
• Reduces risk of premature transmission wear due to fluid loss
• Maintains proper lubrication for output shaft components
• Helps avoid costly transmission repairs related to seal failure

Installation Notes and Tips

• Ensure the transmission housing bore is clean and free of debris before installation
• Use appropriate tools to avoid damaging the seal lips during installation
• Verify shaft and bore dimensions match the seal specifications for proper fit
• Apply a light coating of transmission fluid to the seal lip before installation to ease fitting
• Inspect the output shaft for wear or damage prior to seal replacement

Quality Assurance and Warranty Information

National 4901 output shaft seals are manufactured to meet OEM specifications for fit and function. The use of polyacrylate material and a bi-directional lip design ensures reliable sealing performance under normal operating conditions. This product is backed by National's quality standards and includes a limited warranty against manufacturing defects, providing confidence in its durability and service life.