Why U.S. Testers Rejected the Sherman With Five Engines

October 1942. Ten American tanks undergo desert trials with an engine unlike any other in the Sherman program. Chrysler has connected five six-cylinder car engines into one power plant: thirty cylinders, five crankshafts, and one output. The tanks can pull—but repeated failures leave the test board unconvinced they are ready for combat. So why did nearly 7,500 Shermans go on to be built with this engine? 🔧 Inside this documentary: • Why an urgent engine shortage led Chrysler to use familiar car-engine components • How five crankshafts delivered power through one gear system • Why small accessories caused major trouble in early tests • What engineers changed to make the A57 Multibank more dependable • How the M4A4 Sherman entered British and Allied service, including Firefly conversions The Chrysler A57 was built to solve a wartime production problem. Its story shows what happened after a fast solution met the heat, dust, and maintenance demands of a real tank. Sources: U.S. Army Ordnance Department history and wartime Chrysler A57 maintenance manuals. Subscribe for more stories about the engineering behind World War II machines. #ShermanTank #M4A4 #ChryslerA57 #WW2Engineering #TankHistory #MilitaryEngineering #WW2History #ShermanFirefly #WorldWarII