ArvinMeritor's Meritor 14X tandem drive axle, the lightest axle in its class, has a more robust and efficient inter-axle differential and the fastest ratios - 2.47:1 up to 7.17:1, as well as the widest range of axle ratios. The inter-axle differential - now 20 percent larger - can accommodate increased nominal torque and includes helical gear needle bearings for reduced heat and wear; upsized main differential side bearings for more capacity; and larger input shaft and rear side bearing for strength. The above-centerline design of the inter-axle driveline provides significant improvements, including reduced operating pressures for increased driveline life, less driveline angularity, vibration and energy loss; improved ride quality; and overall longer component life. A newly-designed axle breather feature helps prevent water and other contaminants from entering the carrier while keeping the lube in place.