Shortages of Continental gasoline engines, as used on Sherman I (M4) and Sherman II (M4A1), saw the use of diesel power in this version of the Sherman. The alternative power plant was twin General Motors 6-71 diesel engines. This version was built by Federal Machine and Welding Co., Fisher Tank Division General Motors Corp., and Pullman Standard Car Manufacturing Co.
It was very similar to the Sherman I (M4), of welded construction it’s only major physical difference was its engine deck where the grill arrangement was markedly different. The Sherman III was the first welded-hull Sherman to enter service (entering service before the Sherman I (M4)).
The Sherman III was the second most common Sherman to be used by the British during the war (after the Sherman V).
5033 Sherman IIIs were used by British and commonwealth forces and they saw service with units in North Africa and Italy.
The Sherman III was well liked by its crews as it didn’t have the same reputation as being a Ronson as its Gasoline powered cousins (Sherman I and II), its diesel fuel proving less volatile when the tank was penetrated.