Eaton Detroit TrueTrac LSD Differential For GM Truck 14-Bolt (9.5"). Fits 99-13 HD models using 14 bolt housing with 9.5" ring gear. Also fits 6.0/6.2 equipped models that have the optional 14 bolt housing/9.5" ring gear such as Vortec MAX models. Part Number 914A538
DOES NOT fit standard 1500 Models with 8.5"/8.625" ring gear or 3500HD models with optional 10.5" ring gear.
Arguably the most popular LSD upgrade for the 99-present GM Truck 1500 platform. The OEM differential in the GM Trucks leaves much to be desired once you begin increasing performance. The TrueTrac differential uses helical cut gears and offers considerably more strength than the OE design.
From Eaton:
"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 recommends a petroleum/mineral based GL-5 80W90 gear oil for all Truetrac differentials. Do not use synthetic gear oil or friction modifiers.