Allison Transmission Holdings, Inc. (Allison Holdings) is engaged in manufacturing of fully-automatic transmissions for medium- and heavy-duty commercial vehicles, medium- and heavy-tactical the United States military vehicles and hybrid-propulsion systems for transit buses. Allison transmissions are used in a range of applications, including on-highway trucks, including distribution, refuse, construction, fire and emergency; buses, including school and transit; motorhomes; off-highway vehicles and equipment, including energy and mining, and military vehicles, including wheeled and tracked. It sells its transmissions globally for use in medium- and heavy-duty on-highway commercial vehicles, off-highway vehicles and equipment and military vehicles. In addition to the sale of transmissions, it also sells branded replacement parts, support equipment and other products to service the installed base of vehicles utilizing its transmissions.