Using their enormous manufacturing capacity, GM made contributions in many areas, most significantly by providing vehicles required for the transportation of men and materiel in battle zones.

GM built hundreds of thousands of trucks and vehicles during the war, some of them shipped overseas partially disassembled, only to be reassembled again at various mobile plants in far-off places like North Africa, Persia, India and Burma. Some mobile plants were capable of assembling over 50 heavy trucks a day.

The scope of this operation was staggering considering the logistics of shipping specialized vehicles overseas into different theatres of war, and then supplying them with spare parts and maintenance equipment. The significant role that GM and their employees played in contributing to the success of the Allied war effort, cannot be underestimated.

The Second World War was the first truly mechanized war. It began with Germany's Blitzkrieg and continued as the Allies gained a foothold in Africa, Italy and then northern Europe. And while the infantry still fought and often moved on foot, they had the support of scout cars, tanks, jeeps and trucks.

Trucks were truly the unsung hero of the Allied war effort, hauling everything from reinforcements and food to ammunition. Modified trucks served as ambulances, dental clinics, radio stations and mobile repair shops. Without trucks, the Allies would have been hard-pressed to win the war.

Supporting the war effort on the Homefront was the automotive industry with General Motors (GM) — the largest of the manufacturing companies — at the forefront. By 1942, GM had thrown all of its considerable capacity at manufacturing materials for the Allies.

When the war ended, GM - which included passenger cars from General Motors, Chevrolet, Pontiac, Oldsmobile, McLaughlin-Buick, Cadillac and trucks from Chevrolet and GMC - had manufactured $12 billion worth of war material.

GM began moving towards war production in 1938 as Germany annexed the German-speaking areas of Czechoslovakia. In collaboration with the British War Office, GM changed its trucks' specifications to make them more adaptable for military use.

GM also began studying the feasibility of establishing assembly plants and parts depots at strategic overseas locations. British officials, meanwhile, also looked to General Motors of Canada to produce trucks and other war materials.

When war broke out in Europe in September 1939, Nazi Germany seized GM's plants in Belgium, Denmark, France and Germany. GM then quickly converted its remaining plants in Allied territory to war projects. As soon as the last cars moved off assembly lines, GM shifted its mass production capability to wartime manufacturing, assembling trucks, guns, tanks, aircraft, weapons and numerous components, such as shell fuses.

GM was in an excellent position to assist the Allied war effort. Before the war, GM was already shipping unassembled or knocked down vehicles manufactured in North American to plants in 25 countries throughout the world for assembly. In the two decades before the Second World War, GM shipped 2.5 million American-made vehicles this way. Plants outside the U.S. manufactured another one million cars and trucks. Those practices would prove invaluable during the war.

By the time the U.S. declared war against Germany and Japan in late 1941, GM had already shipped 93,000 trucks to the Allies under the American lend-lease program. Instead of shipping assembled trucks, GM found that packing unassembled trucks into crates increased their transport capacity tenfold.

While transporting trucks unassembled meant a considerable saving of space, it only worked when the ports had infrastructure such as cranes and established assembly plants. So, for destinations that had neither, GM also shipped trucks in two-unit packs. Once off the ships, mechanics could assemble these trucks on the nearest piece of flat ground. To improve efficiency, GM developed mobile plants at dock yards where workers could assemble 50 trucks every eight hours.

Once assembled, trucks were loaded with supplies and driven to the front lines. As the front moved, the mobile assembly plants moved as well. GM also developed reconditioning plants and spare parts depots.

By 1944, GM had 40,000 employees and more than 1,400 projects underway at 23 manufacturing, assembly and special service plants, including the mobile assembly plants operated by the General Motors Overseas Operations Division.

War creates unique challenges, and GM also threw its considerable might behind solving these challenges as they appeared. When the U.S. Army came to GM seeking a solution to transport men and supplies during amphibious invasions, GM developed the DUKW or Duck. This 31-ft. long, six-wheeled vehicle could carry 5,000 lbs. and operate on land and water.

GM also developed mobile repair facilities comprised of three modified trucks, each with a different purpose (machine shop; carpenter, welding and battery repair shop; and spare parts). These trucks allowed the mobile facility to reach and repair damaged naval amphibious craft.

Along with mobile repair facilities for damaged landing craft, amphibious invasion vehicles, and many other innovations, GM also designed improvements to aircraft fuel and two-cycle engines.

While the innovations GM developed during the war usually solved immediate wartime problems, two of GM's executives, drawing on their extensive organizational experience, had a hand in developing chemotherapy. This discovery stemmed from an air raid attack on the Italian port of Bari. German aircraft bombed the harbour on December 2, 1943, sinking 17 American and British ships.

One of those ships, the SS John Harvey, carried a secret cargo of 2,000 mustard gas bombs. The Allies had brought the bombs to Italy as a precaution. If the Germans resorted to gas warfare, the Allies would respond in kind; however, as the John Harvey sank in flames, the bombs exploded, releasing the mustard gas, injuring and killing many Allied servicemen.

A chemical warfare specialist, LCol Stewart Francis Alexander, who recognized the men had been exposed to mustard gas, observed that the gas limited cell division. After reading Alexander's report, Colonel Cornelius P. "Dusty" Rhoads, who was in charge of the Memorial Hospital for the Treatment of Cancer and Allied Diseases in New York, believed small amounts of mustard gas derivatives could attack tumours.

Rhoads convinced GM's Alfred Sloan and Charles Kettering to found the Sloan Kettering Institute in New York in 1945. Developing chemotherapy as a cancer treatment was Sloan Kettering Institute's first project.

In Canada, meanwhile, the shift to wartime production occurred quickly. As the last passenger cars were completed at GM's Canadian plants, the plants were renovated and retooled for war projects. For example, it only took the Regina, Saskatchewan plant six months to completely overhaul its assembly line and begin producing anti-tank gun carriages.

Along with gun carriages, General Motors of Canada plants produced armoured and service vehicles, universal carriers, Browning machine guns, tank components, machine tools, naval gun mountings, shells and shell components, aircraft fuselages and components, gun parts and sights and fire control instruments.

Along with war projects at existing plants, GM also opened new plants to meet demand, such as Border Cities Industries, a specially designed plant in Windsor, Ontario. Border Cities Industries, owned by the Canadian government, employed some 1,000 workers —mostly women— to manufacture Browning machine guns.

GM understood that comfortable and well-trained employees, who worked ten-hour days, meant happy and productive workers. The Border Cities Industries plant at Windsor was bright and clean. It featured a large cafeteria, modern restrooms and other amenities like first-aid rooms with on-site medical staff. Some of the spaces in the plant also had air conditioning.

Along with the ability to retool its operations and take on unfamiliar projects, GM used its experience to cut costs (without cutting quality) to find economies in time, labour and materials. For example, engineers at the Oshawa plant found efficiencies by switching from manufacturing naval gun mounts from cast steel to structural steel.

Cast mounts required more steel (600 pounds more steel than structural steel mounts), they cost roughly $250 more than the structural mounts, and a single flaw in a cast mount meant scrapping the entire mount. A defect in a structural steel mount meant only a portion needed replacement. The switch to producing structural steel mounts also allowed GM to eliminate the expensive tools and equipment it took to make cast mounts.

Along with finding benefits in switching from cast to structural mounts, GM found that switching from brass to zinc alloy for shell fuses reduced costs by 70 percent and saved 3.6 million pounds of brass per month.

GM's experience with mass production also allowed it to eliminate bottlenecks in its operations. In Canada, GM found that its minute inspection process held up production. Shell fuses, for example, had to be free of burrs and rough areas while meeting exact specifications. While the inspection process was essential to ensure its materials and products worked as expected, which for soldiers on the front lines could mean life or death, it was very slow.

At the start of the war, a team of eight inspectors, using hand gauges, measured 115 fuses per hour. Realizing inspection was a bottleneck, GM developed a process where two inspectors working with a series of mounted scientific gauges could accurately inspect 600 fuses an hour.

Other examples of finding ways to increase its efficiency include custom-built massive 15-ton jigs that allowed welders to rotate tank hulls so they could work from the most convenient and comfortable angles. GM also sent tools and fixtures not needed at its plants for its wartime manufacturing projects to plants that needed them.

With its experience and technical knowledge, GM offered the Allies a distinct advantage in not only in manufacturing but in shipping those materials to the war zones and getting it all into the hands of the people who needed that equipment. Overall, GM’s contribution to the war effort falls into three areas: materials, machine tools and manpower

Or as Edward Riley, head of GM's overseas operations, wrote in 1944:

(GM) built up a world organization to distribute these vehicles and keep them running. We established assembly and manufacturing plants in twenty-five countries. We made important savings in ocean freight through improved boxing of components and their assembly overseas.

The spare parts indispensable to vehicle maintenance were stocked, controlled and distributed through numerous warehouses. As time went on, our personnel increased in number and grew in experience. We learned to adapt ourselves to diverse and changing conditions.

It is in this experience and these developed capacities that we have made available as our contribution to the war effort.