1983 GMC Pick-up Truck Differential Spool C2500 - RWD - GM 10.5 in. - 14 Bolt Cover - For Use w/30 Spline Axles - 4.10 Ratio And Down - Rear guaranteed to replace your current 1983 GMC Pick-up Truck Differential Spool C2500 - RWD - GM 10.5 in. - 14 Bolt Cover - For Use w/30 Spline Axles - 4.10 Ratio And Down - Rear. 1983 GMC Pick-up Truck Differential Spool comes new OEM 1983 GMC Pick-up Truck Differential Spool aftermarket new 1983 GMC Pick-up Truck Differential Spool of remanufactured 1983 GMC Pick-up Truck Differential Spool C2500 - RWD - GM 10.5 in. - 14 Bolt Cover - For Use w/30 Spline Axles - 4.10 Ratio And Down - Rear.