This clip from 1942 shows the production of the medium Tank M3 “Grant” in the Chrysler Tank Arsenal, Detroit.
The Medium Tank M3 was an American tank used in the early years of World War II. In Britain, the tank had two names which depended on the turret configuration. Tanks with the US pattern turrets were called the “Lee,” named after Confederate General Robert E. Lee. The ones that were using the British pattern turrets were called “Grant,” named after U.S. General Ulysses S. Grant.
The U.S. Army needed a battle tank and because of the United Kingdom’s requested 3,650 medium tanks, the Lee began production by the end of 1940. The design was a compromise meant to produce a tank as soon as possible, design started in mid-1940 and the first M3s were operational by the end of 1941.
For its time, the M3 had considerable firepower and was properly armoured, but that was balanced out by some drawbacks in its design and shape. These include a high silhouette, the low mounting of the main gun with limited ability to transverse, the riveted construction, and poor off-road performance.
Because the overall performance was not satisfactory , the tank was withdrawn from front line duty as soon as the M4 Sherman was available. The only exception being the use in the remote areas of the Asian Theater where the British forces still used it as late as mid-1944 or later.
In spite of this, Hans von Luck, a famous german tank commander regarded it superior to the best German tank at the time of its introduction, the Panzer IV.
https://www.youtube.com/watch?v=c6Bs29vsZ1c