OER Parts offers a wide selection of Rear End Components for your 1939 GMC Truck. OER Parts offers 1939 GMC Truck Axle Shafts & Parts, 1939 GMC Truck Differential, 1939 GMC Truck Differential Covers, 1939 GMC Truck Differential Hardware, 1939 GMC Truck Differential Tools, 1939 GMC Truck Driveshaft, 1939 GMC Truck Driveshaft Safety Loops, 1939 GMC Truck Gaskets & Seals, 1939 GMC Truck Performance Rear Ends, 1939 GMC Truck Ring & Pinion Gears, and 1939 GMC Truck U-Joints and Parts.