Dorman 697-139 Differential Ring and Pinion

Dorman 697-139 is a standard replacement differential ring and pinion for GM 12-bolt rear axle applications with a 3.90 gear ratio. It directly replaces the original equipment setup on select Chevrolet and Pontiac vehicles, making it a focused solution for restoring drivetrain performance.

Use this ring and pinion set when you need a rear differential gear change or OE-style replacement for a GM 12 Bolt axle. The Dorman 697-139 is built for specific applications including Chevrolet Camaro, Impala, Nova, and Pontiac Firebird models with 3.90 axle ratio fitment.

Key Features

• Gear ratio: 3.9 for GM 12-bolt rear differential applications
• Standard replacement grade for direct OE-style service
• Package contents: ring gear and pinion gear
• Fits rear axle positions only
• Interchange reference: ZG GM12P-390
• Dorman part number 697-139 for application-specific lookup

Fitment Details

• Fits 1964-1972 Chevrolet Bel Air, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1969-1972 Chevrolet Camaro, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1967 Chevrolet Camaro, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1966-1972 Chevrolet Caprice, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1964-1972 Chevrolet El Camino, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1964-1972 Chevrolet Impala, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1970-1972 Chevrolet Monte Carlo, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1969-1972 Chevrolet Nova, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1967-1972 Pontiac Firebird, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1970-1972 Pontiac GTO, rear, GM 12 Bolt; w/3.90 Axle Ratio
• Fits 1964-1967 Chevrolet Malibu, rear, GM 12 Bolt; w/3.90 Axle Ratio

What It Helps Address

• Restores worn or damaged differential ring and pinion gears
• Addresses gear noise caused by excessive wear or incorrect tooth contact
• Supports proper rear axle ratio replacement on GM 12-bolt applications
• Helps correct drivability issues after differential service or rebuild
• Provides a direct replacement path for classic Chevrolet and Pontiac rear ends

Installation Notes

Verify the axle housing is a GM 12 Bolt and confirm the vehicle uses a 3.90 axle ratio before installation. Differential gear setup requires precise backlash, pinion depth, and bearing preload measurements, so professional installation is recommended. This part does not include an installation kit.

Quality Assurance

Dorman supplies standard replacement drivetrain components for specific vehicle applications, and this ring and pinion is engineered to replace the original equipment configuration on listed models. Part number 697-139 is intended for direct application matching on Chevrolet Camaro, Impala, Nova, and related GM 12-bolt rear axle vehicles.