I cannot imagine driving one of these trucks, even stock with an open rear end. I have traction troubles with my nice tight LSD. Two bottle is minimum for the large dana 70 diff, especially if it is the crap that doesn't work well. I would find a drivetrain shop that does work and get a couple doses of what they use. If they work on diff's then they know what works to tame aggressive LSD's.
My LSD has been abused since day one. Many sideways exits from the Fareway store on to the main street on Saturday nights, mud and water up to the rocker panels, snow and ice, and heavy trailers getting pulled around corners.
Michael