During this period of global economic crisis, the number of passenger cars built at Mannheim fell with equal rapidity. From 1,955 cars in 1929, production dropped back to 1,221 (1930), 515 (1931) and then 315 (1932). Nevertheless, the plant managed to escape full closure. On October 1, 1932, Berliner Börsenzeitung reported: “No closure of Daimler-Benz facilities in Mannheim for the time being.” Although consideration had been given to relocating production to Untertürkheim, the Ministry of the Interior for Baden intervened successfully. For the duration of the crisis the foundry was closed, however, and did not reopen until 1933.
The automotive industry as a whole received massive political support with the rise to power of the National Socialists early in 1933. Among other things, this led to a very speedy recovery of the employment situation at the Mannheim plant. That same year the plant was back to full employment and producing the two Mercedes-Benz Mannheim and Nürburg models. A new addition to the program was a 1.5-ton delivery van. And engines for commercial vehicles, boats, locomotives and tractors continued to play an important role in plant production. Finally, in 1937, the Mannheim plant also began truck production.

The outbreak of the Second World War changed the situation of the Mannheim plant completely. The army forced operations to be switched to authorized production of the Opel three-ton truck. Demand for such vehicles during the war years was extremely high. For the Mannheim plant, the Second World War ended on March 23, 1945, when it was occupied by American troops. By this point, air raids had destroyed about 20 percent of all production facilities, and bombs had fallen on almost a quarter of the area. Following the occupation of the plant, a large area at the southern end of the premises was confiscated for use by the American occupying forces.

Production of the three-ton L 701 truck started again at the Mannheim plant in June 1945, making Mannheim the first plant belonging to Daimler-Benz AG to resume activities after the war. At the same time as building this version of the Opel Blitz under license, work began on reconstructing the plant. But the years of shortages after the Second World War made production and new development difficult. Then summer 1949 witnessed the debut of the new Mercedes-Benz L 3250 truck - an event that laid the foundations for the development of the modern Mercedes-Benz commercial vehicles program. Many saw the L 3250 as the vehicle that inspired the rise of Mercedes-Benz to its position as European market leader for medium-duty trucks.

In 1949, the new OM 300 diesel engine series for commercial vehicles made its debut in the Mercedes-Benz L 3250 truck

First bus of the post-war era

It was a most unusual Christmas present: the first bus built at Mannheim in the post-war era - an O 3500 model - left production on December 24, 1949. From now on Mannheim took over some of the responsibility for bus production from Sindelfingen. The bus’s engine, an OM 312, belonged to the new series of engines launched in Mannheim that same year.
In May 1949, the new bus was presented as the O 3250, since it was based on the corresponding truck model. Adopting the traditional approach, the bus body was mounted onto a truck chassis. Then in 1950 the bus was launched under the designation O 3500.

Equipped for all eventualities: An all-weather Mercedes-Benz O 3500 from the Mercedes-Benz Mannheim plant, 1953.