Eaton Detroit Truetrac 30 Spline Differential GM 8.875 Inch 3.73 & Up - 913A315

The Eaton Detroit Truetrac Differential (Part #913A315) is a high-performance, helical-gear limited-slip differential designed for GM 8.875-inch (12-bolt) axles with 30-spline shafts and 3.73 & up gear ratios. Built for strength and reliability, the Truetrac provides automatic, smooth torque transfer to the wheel with the most traction—improving control, stability, and performance both on and off the road.

With no clutches or wearable components, the Truetrac operates quietly and maintenance-free. Its proven all-gear design makes it an excellent upgrade for muscle cars, performance street vehicles, and off-road trucks seeking improved traction without sacrificing drivability.

Note: Eaton differentials for GM 8.5", 8.6", and 8.875" axles require special bearings.

• Vehicles with small bearing bores (2.89" race O.D.), typically pre-1999: use bearing LM102949 and race LM102911.

• Vehicles with large bearing bores (3.06" race O.D.), typically 1999 and later: use bearing LM603049 and race LM603012.

Features:

• Helical-gear, torque-biasing limited-slip design for smooth, automatic engagement

• Maintenance-free operation—no clutch packs or friction modifiers required

• Durable, all-gear construction for superior strength and longevity

• Enhances traction and handling under acceleration or on uneven terrain

• Optimized for GM 8.875" 12-bolt axles, 30-spline shafts, and 3.73 & up ratios

• Ideal for street, performance, and off-road applications

Specifications:

Fitment:
Compatible with GM 8.875-inch (12-bolt) rear axles used in various passenger cars, muscle cars, and trucks.

Ideal Usage:

• On Road: Street & Muscle, Drag Racing, Circle Track, Restoration, Work Truck / Towing

• Off-Road: Light Trail, Rock Crawl, Sand Sports, Extreme Off-Road, Work Truck / Towing