Two new versions of Mack Trucks’ mDRIVE HD automated manual transmission (AMT are the first proprietary automated manual transmissions to offer low reduction gear ratios.
Available in direct or overdrive configurations, the new Mack mDRIVE HD 13-speed offers a low reduction gear ratio designed for easier starting on steep grades or when the truck is under heavy load. The mDRIVE HD 14-speed, available only in an overdrive configuration, adds a second ultra-low, creep-speed reduction gear. Both transmissions offer up to four reverse gear ratios.
“We launched the original mDRIVE HD in response to customers looking for an AMT capable of withstanding tough vocational applications,” said John Walsh, Mack vice president of marketing. “Now, with the mDRIVE HD 13- and 14-speeds, we’re taking the next step and combining low-speed capabilities.”
The new Mack mDRIVE HD models share their architecture with the standard mDRIVE HD, including reinforced internal components and the same gear ratios for the 12 forward speeds. Addition of the low reduction and multispeed reverse gears is made possible by a short extension added to the front of the transmission case. The new transmissions are less than 5 in. longer and only 90 lb. heavier than the standard mDRIVE HD, maintaining a weight advantage of nearly 150 lb. over automatic transmissions.
The new low gears not only improve performance in off-road, heavy haul and construction applications, but they also enable use of a faster rear axle ratio to improve on-road fuel economy. For the first time, customers will now have the option to spec the mDRIVE HD in Mack Pinnacle truck models, including the new mDRIVE 13- and 14-speed models.
All Mack mDRIVE transmissions, including the standard mDRIVE and mDRIVE HD, were updated with a redesigned gearbox control unit and a new clutch with a larger torsional damper to reduce driveline vibration. Component wear monitors were added to enable predictive maintenance.
Mack stretched its warranty coverage of all mDRIVE transmissions and clutches used in heavy- or severe-duty applications. The mDRIVE and mDRIVE HD standard warranty now extends to 36 months with unlimited miles for heavy-duty applications. In severe-duty applications, warranty coverage is extended to 12 months and unlimited miles for the mDRIVE, and 24 months with unlimited miles for the mDRIVE HD.
The mDRIVE updates include several improvements to power take-off (PTO) controls, including new main cab harnesses for all mDRIVE models, a reinforced range housing to handle higher PTO bending torque and an all-new cab-mounted Body Builder Module. The Body Builder Module is customizable, with user-configured software parameters to control engine speed and block reverse gears when the PTO is engaged. Dual PTOs are now supported.
Available exclusively with Mack’s MP series engines, the Mack mDRIVE HD 13- and 14-speed AMTs will be available for order in August on Mack Pinnacle, Granite and Titan by Mack models.