The Yukon mini spool for GM 8.5-inch with 28-spline axles installs into a standard open carrier to replace spider gears and deliver continuous 100% drive to both wheels. These mini spools are a budget-friendly traction option for off-road or competition use; Yukon advises that they are not recommended for regular street-driven vehicles.
Yukon Gear Mini Spool For GM 8.5in w/ 28 Spline Axles