1915: James A. Allison founded the Speedway Team Company, the business that would eventually evolve into Allison Transmission, to support his Indianapolis 500 racing activities. Since the beginning, quality and workmanship have been the foundation of the company's business philosophy. The following quote from James Allison, which exemplifies Allison’s brand promise, hung on a sign in his shop: "Whatever leaves this shop over my name must be of the finest work possible." 

1917: One day after World War I is declared, James A. Allison instructs his Speedway Team Company to cease all activities associated with racing and cancels the Indianapolis 500. The Speedway Team Company supports the U.S. war effort by developing high-speed crawler-type tractors for hauling artillery and battlefield equipment, aircraft engines, tank components, tank tracks, production superchargers and reduction gearboxes.

1920: The Speedway Team Company changes its name to the Allison Engineering Company to align with the company’s evolution beyond racing and the Speedway. Allison is recognized by the U.S. Bureau of Aircraft Production for its Liberty aircraft engines, firmly establishing its reputation for quality. Soon after the end of World War I, Allison Engineering produces precision reduction-gear assemblies for the nation’s Liberty aircraft engines, as well as V-drive marine gears, four-cylinder generator sets and 12-cylinder marine engines.

1928: Following James Allison’s death, Allison Engineering Company is sold to General Motors under the stipulation that Allison headquarters remain in Indianapolis for at least 10 years. To this day, Allison Transmission's headquarters and primary manufacturing base remain in Indianapolis.

1937: Allison Engineering Company’s V1710 12-cylinder liquid-cooled aircraft engine passes its 150-hour acceptance trials at Wright Field, making it the first 1,000 horsepower American engine to accomplish this task. The V1710 goes on to power many of the U.S. Army Air Corps’ most famous fighters. 

1941: On December 7, Pearl Harbor is attacked, and the U.S. enters World War II. The Allison Division of General Motors’ V1710s, V3420s and their variants are called upon to support the U.S. Army Air Corp and the nation’s allied air forces. Production climbs to 1,000 engines a month. Prior to Pearl Harbor, capacity had been at 225 engines a month.

1943: As women join the workforce to support the war effort, the Allison Division of General Motors reaches a record number of female employees, more than 30% of the total workforce. Production peaks at approximately 3,000 engines a month and employment reaches an all-time high of 23,019. 

1947: Following the war, Allison officially enters the commercial transmission field. The first Allison “V” (angle drive) transmission is shipped to General Motors Truck and Coach Division. GM buses equipped with Allison transmissions will transport millions of passengers throughout North America for more than 30 years.

1956: The Allison Division of General Motors finalizes a six-speed design incorporating the Allison hydraulic retarder for Chevrolet medium-duty trucks. The company also introduces CTP4, the first on-highway automatic transmission, employing a four-element torque converter, six forward speeds and one reverse. GM, Ford and Dodge commercial trucks were the first to offer vehicles with this transmission.

1969: Allison announces the new four-speed AT540, the first automatic transmission for medium-duty trucks. 

1973: Following the merger of General Motors’ Allison Division and Detroit Diesel Division into the Detroit Diesel Allison Division, the company's CLTB750 is announced as the first fully automatic transmission in the U.S. for large trucks, scrapers and other heavy-duty, off-highway vehicles. In addition, the fully automatic transmission becomes the standard powertrain for most U.S. Army trucks, marking a major milestone for Allison.

1975: The first new transit coach transmission since 1950 is announced: the three-speed, fully automatic V730. Hundreds of thousands of these transmissions will eventually power city buses throughout North America.

1982: Allison launches the HT 747™ transmission, a first of its kind, built for articulated city buses. This same year, the DP-8962™, a new generation of heavy-duty automatic transmissions is introduced.

1983: Allison unveils the CLT9880™ transmission for use in the production of oil and natural gas. 

1988: Allison announces the AT 542™ transmission for Class A motor homes. Variations of this transmission still power the majority of motor homes in North America.

1999: General Motors and Allison Transmission launch an electric hybrid bus program for the New York City Transit Authority. In addition, the company dedicates the new Allison Electric Drive Technology Development Center.

2003: Allison Transmission converges with the General Motors Powertrain Division, which designs and manufactures engines, transmissions, castings and components. Allison’s H 40/50 EP electric hybrid propulsion system for city buses begins production.

2007: After GM announced its plans to divest Allison Transmission the previous year, The Carlyle Group and Onex Corporation acquire the Allison Transmission Division for $5.6 billion, and Allison Transmission, Inc. becomes independent from General Motors. Lawrence E. Dewey is named Chairman and CEO. 

2012: Allison Transmission Holdings Inc., begins trading on the New York Stock Exchange under the symbol ALSN. CEO Lawrence E. Dewey informs investors that the company will pursue several strategic priorities including expanding global market leadership, increasing emerging market penetration, focusing on new technologies and product development, and delivering strong financial results.

2020: The Vehicle Electrification + Environmental Test Center opens on Allison’s Indianapolis campus, allowing seasonally independent and power-agnostic testing. In addition, Allison announces the eGen Flex, a next-generation electric hybrid sytem for transit buses. The 3414 Regional Haul Series transmission is also introduced for medium-duty distribution and delivery trucks. In October, Allsion begins rolling out its eGen Power family of fully electric axles.

2021: Allison expands its off-highway portfolio by launching both the FracTran, a revolutionary hydraulic fracturing transmission, and TerraTran, a solution for global mining and construction applications. 

2022: Allison opens the Innovation Center, a new 96,000-square-foot facility featuring enhanced product and technology development and validation capabilities to support its customers, industry partners and suppliers.