Rear Axles



rear axlesYou want drive axles that last, require little maintenance and minimize unexpected downtime. The S40 Series fills all those needs. Its housing is made from fabricated steel to effortlessly handle heavy loads up to 44,000 lbs. — an ideal choice for highway applications. The S40 axle housings have tighter tolerances and fewer weld joints for greater reliability and longer life. The bowl cover is a one-piece, seamless design that integrates into the housing rather than a separate welded-on piece for more durability and less leak paths. Also, dirt and debris can’t get inside to damage components.


rear axlesMack has strengthened suspension joint clamp integrity on the S40 Series. The corners are squared off to minimize compression and form a tighter, longer-lasting connection. Suspension brackets use set screws and are then welded in place to boost bracket-to-axle weld joint integrity. The S440 is ideally engineered as a lighter alternative for heavy-duty use at 44,000-lb. capacity. R-Series industry-standard wheel ends are used on both axles so wheel end bearing and brake compatibility is virtually ensured.


The S46 is a premium drive axle made of cast ductile iron and carries loads rated to 46,000 lbs. This severe-duty workhorse saves weight by casting thicker reinforcing to only the parts that take the brunt of the load. The S46 is the strongest 46,000-lb. axle Mack has ever built.

Download the Mack Powertrain brochure