Loading... Please wait...GM 8.6" 1500 Rear End Axle Assembly for GM 8.6" 10 Bolt SUV Rear End in a 3.42 Gear Ratio. Standard Open Differential (Opt GU6), Fits fits model years 2007-08, 2WD & 4WD. Replacement rear axle assemblies from USA Standard come complete with all differential components in one part number for easy, bolt-on installation.