The approach taken in the design, development, and application of an Oshkosh powershift transmission for on/off-highway truck use is described.The Oshkosh transmission design has a building block concept, and in its basic form consists of a two-speed splitter auxiliary attached to the four-speed main drop box to provide a transmission with eight forward speeds and two reverse speeds. The two-speed splitter auxiliary may be omitted to provide a transmission with four forward speeds and a single reverse speed.The eight-speed transmission will be capable of use with high speed, low torque engines, or with low speed, high torque engines. This is accomplished by changing the input ratio gears. The overall ratio of the transmissions may also be changed to match tire size and/or axle ratios. The ratio changes for engine speed-torque and/or overall ratio may be made without affecting the transmission range or physical configurations.