ArvinMeritor’s all-new Meritor 14X tandem drive axle is said to be "an advanced evolutionary axle system built on the legacy of the RT145." That’s a pretty good engineering pedigree, with nearly two million RT145s built since 1985. Manufacturing starts in two North Carolina factories in June, with planned deliveries to all major North American OEMs. 

New developments in the 14X include a more robust and efficient inter-axle differential, the fastest ratio and widest range of axle ratios, and several other design enhancements "while continuing to be the lightest axle in its class,” says ArvinMeritor.

The inter-axle differential (now 20% larger) can accommodate the increased nominal torque, up to 2050 lb ft in certain applications, of today’s diesels. Its helical gear needle bearings bring reduced heat and wear; its upsized main differential side bearings add capacity; and its larger input shaft and rear side bearing increaser strength, the company says.

Premium ‘amboid’ design is standard equipment. The above-centerline design of the inter-axle driveline is said to provide real improvements: reduced operating pressures for increased driveline life, less driveline angularity, vibration and energy loss; improved ride quality; and overall longer component life. 

The very complete range of ratios will appeal to many – the 14X offers the fastest ratio in the industry, 2.47:1 and goes all the way up to 7.17:1. That ensures coverage for nearly every application and specific engine manufacturers’ EPA 2010 recommendations.

For example, among the many carriers that have road-tested the new axle already, accumulating more than six million miles in the process, is a Tennessee fleet that wanted to lower engine rpm at cruise speed with direct transmissions. It tried the 14X equipped with the 2.47:1 ratio and brought engine speed into the economy range they needed, saving money in the process..

Among other new features, there’s the optional DualTrac housing – an intermediate track housing designed that allows operators to run wide-base single tires with the equivalent bearing life of axles equipped with dual-tire configurations, while still offering convertibility back to duals.

The newly-designed axle breather helps prevent water and other contaminants from entering the carrier while keeping the lube in place.

The 14X axle is the signature member of the company’s ‘MPG Series’, products that are optimized for improved total life-cycle costs www.mpgseries.com