Mack Trucks held a ride and drive event for journalists at its customer center in Allentown, PA, to demonstrate the capabilities of the vocational version of its mDrive automated manual transmission (AMT) dubbed the "mDrive HD." Journalists were provided the opportunity to test three different Mack Granite models equipped with the mDrive HD - two spec'd out as dump trucks one a concrete mixer - on the center's durability course, circular track, and an incline sporting a 15% grade.