Automatic transmissions in line haul vehicles had been practically non-existent until the Allison HT750-CRD model was specifically designed for that vocation. Prior to the start of production of this new automatic, a comprehensive market survey was conducted to determine line haul carrier interest in the automatic as a solution to manual transmission related problems. As a result of the survey, an extensive Fleet Evaluation Program was initiated to firmly establish product acceptance, product durability, and cost comparisons with manual-equipped units. The program was designed to cover a broad range of vehicle duty cycles and vehicle and engine makes.
The findings of more than two years of fleet testing are discussed, along with the initial design of the transmission and its controls and transmission refinements and installation improvements derived from the program.