National 3720 Differential Pinion Race

National 3720 Differential Pinion Race Overview

The National 3720 differential pinion race is engineered for reliable driveline performance in select Hummer, Oldsmobile, and Pontiac vehicles. Designed as a taper bearing cup, this component ensures precise fitment and durability for models such as the Hummer H1, Oldsmobile 88 and 98, and Pontiac Catalina and Starfire.

• Cup bore diameter: 3.6718 inches (93.2640 mm)
• Cup length: 0.9375 inches (23.8130 mm)
• Cup radius: 0.1250 inches (3.1750 mm)
• Part type: Taper bearing cup for differential pinion
• Compatible with Hummer H1, Oldsmobile 88 and 98, Pontiac Catalina and Starfire

Technical Specifications and Design Details

The National 3720 differential pinion race features a precisely machined cup bore of 3.6718 inches (93.2640 mm), providing a secure seating surface for the bearing. Its cup length of 0.9375 inches (23.8130 mm) and cup radius of 0.1250 inches (3.1750 mm) are designed to match OEM specifications, ensuring proper alignment and load distribution within the differential assembly. This taper bearing cup is critical for maintaining the correct preload and smooth rotation of the pinion gear, contributing to the overall driveline efficiency and longevity.

Compatible Vehicles and Applications

This differential pinion race is compatible with specific models including the Hummer H1, Oldsmobile 88 and 98, and Pontiac Catalina and Starfire. It is intended for use in driveline and axle assemblies where a taper bearing cup is required to support the differential pinion gear. The National 3720 part number corresponds directly to OEM replacement specifications for these vehicles, making it suitable for maintenance and repair tasks.

• Restores proper bearing fitment in differential pinion assemblies
• Addresses issues related to bearing wear or damage
• Helps eliminate differential noise caused by worn races
• Prevents premature bearing failure due to improper seating
• Supports smooth and reliable driveline operation

Installation Notes and Tips

When installing the National 3720 differential pinion race, ensure the cup bore and seating surfaces are clean and free of debris. Use appropriate tools to press the race evenly into the differential housing to avoid distortion. Verify the cup length and radius match OEM specifications to maintain correct bearing preload. Proper installation is essential to prevent premature wear and ensure optimal performance.

Quality Assurance and Warranty

National manufactures the 3720 differential pinion race to meet strict quality standards, ensuring dimensional accuracy and material integrity. While specific warranty details are not provided, National parts typically adhere to industry standards for durability and reliability. Using this part helps maintain the driveline performance expected in Hummer, Oldsmobile, and Pontiac vehicles.