After determining multiple weaknesses & shortcomings in the M26 Pershing tank after WWII, it was decided that the vehicle would go through various upgrades. Revisions included a new engine and transmission system combined with strong armor protection and the proven 90mm main gun. This improved tank was first designated ‘M26E2’ carrying on the Pershing family name. However, upgrades & revisions became so numerous that it essentially became an entirely new tank, and in 1949 was ultimately redesignated ‘M46’ by the ordnance bureau and renamed in honor of American 4-general George S. Patton, commander of the U.S. Third Army during WWII. In total, some 800 M26’s were rebuilt into M46’s at the Detroit Tank Arsenal.
Based on the hull of the M26, the 48.5 ton M46 was powered by the 810 horsepower Continental AVDS-1790-5A series V-12, air-cooled, twin-turbo, gasoline engine coupled with a General Motors/Allison CD-850-3 series cross drive transmission system with 2 forward gears and 1 reverse gear, resulting in the engine compartment being extended by a foot in length and a complete redesign of the deck. In addition, the drive sprockets were repositioned further to the upper rear and small track-tension idlers were installed behind the last road wheels. The M46 could reach a maximum speed of 30 mph (48 km/h) and enjoyed an operational range of 80 miles (130 km). The M46 utilized the turret from the M26 and was armed with the 90mm M3A1 main gun with a coaxial .30 caliber M1919A4 machine gun. The main gun featured a bore evacuator and a single baffle muzzle brake. 70 rounds of ammunition for the main gun were stored inside the tank, allowing the crew to select between HEAT, AP, and HE rounds. A second .30 caliber machine gun was mounted in the 5-inch (102mm) thick armored bow at the right of the driver’s station, and a .50 caliber machine gun was mounted in a pintle on the turret roof. The vehicle was crewed by five men - the tank commander, driver, assistant driver/bow machine gunner, a dedicated gunner and a loader.
The first M46 Patton tanks (belonging to the 6th Tank Battalion) landed in South Korea on 8 August 1950, with some 200 arriving in country by the end of the year. The M46 Pattons proved far superior to the Soviet-built T-34/85 tanks fighting against them, and ultimately allowed all M26 Pershings & most M4A3 Shermans to be withdrawn by the end of 1951. The M46 was itself withdrawn from service soon after the end of fighting in Korea, but was temporarily leased in limited numbers to several NATO allies for training crews & mechanics how to operate it’s replacement, the M47 Patton.