Dana’s Dual Range Disconnect
First revealed at the Mid-America Trucking Show in March, Dana's Dual Range Disconnect drive axle system offers the fuel savings benefit of a downsped 6x2 drivetrain and the performance benefits of conventional 6x4 setup with a mid-range axle ratio. The key word here is disconnect. While running at speeds up to about 54 mph, the system functions as a 6x4 with torque going to all four wheels for optimum traction. It also runs at a 3.10:1 ratio for better performance and startability. Above 54 mph, the interaxle driveshaft disengages, leaving the driving to only the forward drive axle. Interestingly, the axle ratio of the forward axle is 2.26:1, which lowers engine rpm and in effect creates a downsped drive train. The benefit, of course, is better fuel economy resulting from a 300-400 rpm drop in engine speed.