Mack Trucks has introduced drivetrain systems that executives said improves load-hauling efficiency and fuel economy of their Pinnacle tractor for bulk haulers: Load Logic, which controls the top two gears of its mDrive automated transmission, and a self-operating 6x2 liftable pusher axle setup.

For applications that routinely haul out heavy and return empty, Mack Load Logic and the 6x2 with liftable pusher axle are designed to monitor trailer weight and adjust the truck’s driveline configuration to boost fuel efficiency without degrading performance.

“Mack Load Logic and the 6x2 with liftable pusher axle are great examples of Mack’s focus on application excellence,” said Stephen Roy, president of Mack Trucks North America.

Load Logic integrates an advanced sensor in the rear suspension with mDrive automated manual transmission. When a fully loaded trailer is detected, mDrive operates as a direct drive transmission, locking out 12th gear for increased performance and pulling power. When an empty trailer is detected, the transmission switches to overdrive, enabling 12th gear to lower cruise rpms and maximize fuel efficiency.

Load Logic is available with Mack’s Super Econodyne system that operates the engine at low rpms. In this combination, Load Logic delivers up to an additional 2% improvement in fuel efficiency when compared to a standard engine rating.

Similarly, the 6x2 with liftable pusher axle is also capable of determining payload by using sensors in the rear suspension and either lifting or lowering the foremost rear axle. When an empty load is detected, the axle lifts, allowing the tractor to operate as a 4x2 for less gear drag, better fuel efficiency and reduced tire wear. For full loads, the same axle is lowered to provide additional stability and distribution of the trailer’s weight on the fifth wheel.

To deliver optimal traction, the system’s suspension pressure and ride height are continuously monitored and adjusted to maintain a load bias toward the drive axle. In addition, three driver-selectable traction control modes are available via a dash-mounted switch:

• Enhanced Traction – Enhances low-speed traction for improved starts, docking and slippery road conditions.

• Optimized Traction – The default setting, Optimized Traction maximizes load to the drive axle. If wheel slip is detected, the system can temporarily increase load to the drive axle for 30 seconds to provide improved traction.

• Basic Traction – Lowers the lift axle regardless of suspension load and maintains a 50/50 load split between the lift axle and drive axle during loading or unloading, prolonged stops or soft-surface areas where the load is best supported by both axles.

During normal operation, control of the lift axle is automatic based on payload. The system offers a manual control feature that enables a driver to raise or lower the suspension for easier landing gear retraction or trailer hook-up respectively.

“The Mack Pinnacle model is already an ideal workhorse for weight and fuel-conscious customers,” said Roy Horton, director of product marking. “With these new solutions, customers no longer need to choose between better efficiency and better productivity. Load Logic combines the performance of direct and overdrive transmissions into one, and our 6x2 with liftable pusher axle enhances traction, ride and handling characteristics, while still delivering increased productivity.”

The Pinnacle model offers other lightweight and fuel-saving options to benefit customers with regional, bulk and tanker haul and diminishing load applications, Horton said. Among other things, it can be spec’d with the MP7, a 10.8-liter diesel that weighs about 400 pounds less than a typical 13-liter-class engine.