Detroit Locker 913A481 Truetrac Limited Slip Differential GM Spline - 8.5/8.6 10-Bolt 30

The Detroit Locker 913A481 Truetrac is a helical gear-style limited slip differential designed for GM 8.5 and 8.6 inch 10-bolt rear axles with 30-spline axle shafts. This performance differential utilizes a patented parallel-axis planetary helix gear design to provide automatic torque transfer and enhanced traction without the maintenance requirements of traditional clutch-type limited slips.

Key Features:

• Helical gear-driven design with no clutches to wear out
• Automatic torque splitting—transfers power to the wheel with better traction
• Smooth, quiet operation under normal driving conditions
• Maintenance-free sealed unit requires no friction modifiers
• Steel carrier construction for durability
• Compatible with 2.73 gear ratio and up
• Fits 30-spline axles with 1.32-inch diameter

Application Notes:

• Designed for GM 8.5/8.6 inch 10-bolt rear axles
• Requires special carrier bearings (not included)
• For 1999+ vehicles with 3.06-inch bearing bore: use bearing LM603049 and race LM603012
• For pre-1999 vehicles with 2.89-inch bearing bore: use bearing LM102949 and race LM102911
• Use petroleum-based GL-5 80W90 gear oil—do not use synthetic oil or friction modifiers
• Ring gear bolts to carrier for installation

The Detroit Truetrac operates like an open differential during normal driving, automatically engaging when traction conditions warrant without any driver input. This makes it ideal for street performance, muscle cars, towing applications, and light off-road use. The robust helical gear design delivers reliable traction for drag racing, circle track, street performance, work trucks, and restoration projects.