OER Parts offers a wide selection of Oil System & Parts for your 1956 GMC Truck. OER Parts offers 1956 GMC Truck Bypass Valves, 1956 GMC Truck Dipsticks and Tubes, 1956 GMC Truck Filter Adapters, 1956 GMC Truck Oil Coolers, 1956 GMC Truck Oil Filters, 1956 GMC Truck Oil Pan Baffles, 1956 GMC Truck Oil Pans, 1956 GMC Truck Oil Pickup Tubes, 1956 GMC Truck Oil Pumps, and 1956 GMC Truck Oil Senders.