The core capability of Stewart & Stevenson LLC - ADDA Division d/b/a Atlantic Detroit Diesel Allison and Atlantic Power Systems is the sale and expert service of diesel and alternative fuel engines, transmissions, power generation systems and a wide range of related products, components, parts and accessories. ADDA represents the most respected brands in the businessnames like: Detroit Diesel, MTU, Mercedes-Benz, Allison Transmission and more. ADDA also provides comprehensive service for a variety of equipment in both On-Highway and Off-Highway markets: medium and heavy-duty trucks, buses and coaches; fire and emergency vehicles; power generation systems; marine propulsion and support equipment (for both commercial vessels and pleasure-craft); and construction and industrial machinery. Atlantic Detroit Diesel Allison is the distributor for five boroughs of New York, Long Island, the eastern portion of New York State, as well as the northern portion of New Jersey, the states of Connecticut and Vermont and the two western counties in Massachusetts. We offer our customers quality products backed by service programs and effective management. We strive to keep customers operating their equipment at the lowest cost and highest productivity. At Atlantic Detroit Diesel-Allison and Atlantic Power Systems, our customers come first.