Eaton Detroit Truetrac 30 Spline Differential GM 8.5/8.6 Inch 913A481

Eaton Detroit Truetrac TT70P53041 (GM 8.5/8.6" 10-bolt): Helical-gear, maintenance-free limited-slip that quietly biases torque to the tire with grip—no clutches, no additives—delivering smooth, durable traction. Ideal upgrade for street/strip and light off-road while keeping OE-like manners.

Fits:

• GM 8.5/8.6" 10-bolt rear axle, 30-spline, 3-series (2.73 & numerically higher)

• GM passenger cars (1973–1997) with the 8.5" 10-bolt — e.g., A-/B-/F-/X-body: Chevelle/Malibu & El Camino; Cutlass/442; LeMans/Grand Am; Skylark/Regal; Caprice/Impala; Camaro/Firebird; Nova/Ventura/Omega/Apollo

• GM half-ton trucks/SUVs with the 8.5" 10-bolt (1973–1996) — e.g., C/K 1500, Suburban, Blazer/Tahoe

• GM trucks/SUVs with the 8.6" 10-bolt (1999-up) using 30-spline axles

• Always verify axle type, spline count, and gear ratio before ordering

• Use a quality GL-5 petroleum/mineral gear oil (no limited-slip friction modifier). That’s Eaton’s recommendation because friction modifiers can reduce the Truetrac’s torque-bias performance.

Manufacturer Warranty: Eaton limited warranty; terms vary by region/application. See Eaton’s official warranty documentation and your invoice for specifics.

Manufacturer Notes (memory): Axle: GM 8.5/8.6" 10-bolt • Spline: 30 • Carrier: 3-series (2.73+) • Type: Helical-gear Truetrac (no clutches/additives) • Bearing note: pre-1999 use LM102949/LM102911; 1999-up use LM603049/LM603012.