1981 GMC Suburban Differential Spool K1500 Suburban - GM 8.5 in. - w/ 10 Bolt Cover - 28 Spline - Spartan Locker - Installs into standard open carrier case - Front guaranteed to replace your current 1981 GMC Suburban Differential Spool K1500 Suburban - GM 8.5 in. - w/ 10 Bolt Cover - 28 Spline - Spartan Locker - Installs into standard open carrier case - Front. 1981 GMC Suburban Differential Spool comes new OEM 1981 GMC Suburban Differential Spool aftermarket new 1981 GMC Suburban Differential Spool of remanufactured 1981 GMC Suburban Differential Spool K1500 Suburban - GM 8.5 in. - w/ 10 Bolt Cover - 28 Spline - Spartan Locker - Installs into standard open carrier case - Front.