Eaton Detroit Truetrac Limited Slip Differential for 30-Spline GM 8.5/8.6 in 10 bolt rear axle.
Arguably the most popular LSD upgrade for the 99-13 GM Truck 1500 platform using the 10 bolt rear end (8.625" ring gear). The OEM G80 differential in the 99-13 Silverado/Sierra and fullsize SUV applications is notoriously weak and often one of the weakest links in the drivetrain once you begin increasing performance. The TrueTrac differential uses helical cut gears and offers considerably more strength than the OE design.
"Eaton Detroit Truetrac differentials use a patented design of parallel-axis planetary helix gears to provide a quiet, automatic splitting of torque. They perform like a limited-slip differential under normal driving conditions, automatically transferring torque to the wheel with better traction when ground conditions warrant. These replacement units are available for dozens of axle applications."
Eaton differentials require special bearings. For 1999 and prior- bearing LM102949 and race LM102911 are required. (2.89 O.D. race) For applications 1999 and newer with race O.D. of 3.06 in. bearing LM603049 and race LM603012 are required.
Eaton recommends a petroleum/mineral based GL-5 80W90 gear oil for all Truetrac differentials. Do not use synthetic gear oil or friction modifiers.