Jeff your response at least has me pointed in a direction. Do you believe that the gearboxes were all assembled in one plant and then shipped to all the plants. Similar to rear ends. It makes sense that the main case came from a foundry Like dif or Cleveland. Then the castings would go to a sub assembly plant and ultimately throughout all the ford assembly plants. Similar to a power steering pump. If this was true then no big difference between San Jose, Dearborn, metuchen, st Louis or Atlanta, mustang, fairlane, galaxy. Ford or mercury.