Mack truck's lifter drive axle saves fuel and maintenance costs

Sensors lift or lower the axle to decrease or increase traction.

The 6x2 with liftable pusher axle is designed for applications that haul out heavy and return empty, such as bulk haul. The addition of Automatic Standby Mode eliminates the need for the driver to manually push buttons to initiate standby mode, simplifying operation. When the ignition is off, Automatic Standby equalizes the suspension pressure, preventing the rear axle from being overloaded. The driver does not have to remember to initiate the standby mode and does not need to remember the button sequence to put it in standby.

The axle monitors trailer weight and adjusts the truck’s driveline configuration to boost fuel efficiency without impacting performance. It is 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 drag, better fuel efficiency and reduced tyre wear, which helps lower maintenance costs. For full loads, the same axle is lowered to provide additional stability and distribution of the trailer’s weight.

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 (ET) – Enhances low-speed traction for improved starts, docking and slippery road conditions.
  • Optimized Traction (OT) – 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 (BT) – 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 areas that require 50/50 load splits between tandem 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. Source  

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