As the United States entered World War II, the Motor City was directed to throw all its considerable might into arms production. Here’s Cadillac’s contribution.

When the United States entered World War II on December 8, 1941, the Motor City was transformed into an industrial war machine almost overnight. Production of civilian automobiles was finished up by February 10, 1942—a mere 69 days after Pearl Harbor. Fortunately, there was some warning. In May of 1940, President Franklin D. Roosevelt had appointed WIlliam S. Knudsen of General Motors to lead Detroit’s manufacturing effort to provide arms to the Allies in Europe, where the war was already raging. In January of 1941, Roosevelt had  called the USA’s tremendous manufacturing capability “the great arsenal of democracy.”

M5 Stuart tank at Normandy

The Cadillac division’s contributions to the war effort were many, including aircraft engine parts forthe GM Allison division. However, its major initiative was an adaptation of the Stuart M3 light tank that exchanged its Continental 7-cylinder radial engine for a pair of Cadillac V8s (110 hp each) and Hydra-matic transmissions. Renamed the M5, this tank was fast, maneuverable, simple to operate, and with its standard automotive drivetrain, relatively easy to manufacture. They were produced by the thousands, as was the M8, a 75-mm Howitzer motor carriage built on the same chassis.

M24 Chaffee production line at Cadillac Clark Street plant in Detroit 

By mid-1943 a replacement for the M5 was successfully developed, the M24 Chaffee, using the same Cadillac V8s and Hydramatic transmissions with improved armor and a much more powerful 75-mm gun. The first M24s arrived in Europe in November of 1944 in time to serve in the Battle of the Bulge, but production was halted at the end of the war before the contract was completely filled. Chaffees later served early in the Korean war and in the armed forces of U.S.-aligned nations around the world.

Even though all the automakers, Cadillac included, were totally engaged in the war effort with cost-plus contracts from the federal government, they continued their heavy  advertising buys in magazines and newspapers, keeping the publications in business and giving the civilians at home some semblance of normal life. The ads were heavy on patriotic messaging and proudly boasted the companies’ contribution to the war effort. The Cadillac ads, naturally, often featured M5 tanks and their Cadillac V8 engines.

By early 1945 when the war’s outcome was becoming clear, the automakers were allowed to make limited preparations for eventual civilian car production. Victory in Europe came on May 8 and victory over Japan on September 2. On October 17, just 45 days later, the first 1946 Cadillac, a very slightly warmed-over 1942 model, rolled down the production line at Clark Street (below). But in truth, due to manpower and materials shortages it would take the U.S. auto industry a few more years to return to normal production.