I have a detroit Tru Trac in my k2500, 14 bolt and its awesome. Quiet, zero maintenance, gear driven...I have run them in jeeps too for the simplicity of an "auto locker" and I feel its a strong upgrade for out trucks for towing and street manners when addressing traction devices. Its a little more $ but worth it. It takes just good ole diff fluid- no additives needed.
From ECGS: "GM 14 BOLT 10.5 FULL FLOAT Detroit TrueTrac, TT 915A545 30 Spline, 4.10 and Down. A very good limited slip, the clutchless design makes this an outstanding product that does not wear out. It also does not require special fluid. No clutches to burn, crack or spin. If your looking for more traction but need good road manners this is a great option."