The vehicle industry in general and the trucking industry in particular have found that mechanical power conversion of gas turbine engines for prime mover needs requires the use of an automatic transmission. Multiple gear ratios are required to keep the engine running within its most efficient operating range. Power shifting is required to prevent engine runaway during shifts and eliminate the attendant difficulty in matching of engine and transmission speeds for smooth shifting.The HT-740T automatic transmission was designed to provide optimum usage of gas turbine engines in trucks and buses.In this paper a description of the transmission gearing arrangement and controls is presented to show how the transmission functions and utilizes signals from the gas turbine engine. Other transmission features peculiar to gas turbine applications are also presented. In addition, the extensive development program to which this product has been subjected is described.