Mack Trucks introduced the Mack S852, an 85,000-lb. gross axle weight rating of its proprietary tandem drive axles, which is available for order now. Customers can spec it for specialized severe-duty or heavy-haul applications on Mack Granite models. For extreme loads at slow speeds, the S852 tandem drive axles have a creep rating of 105,000 lbs.

Today’s Mack drive axles are engineered with a double-reduction design and include several design advantages implemented through continuous research and development efforts, according to Mack, such as the use of Durapoid bevel and helical gears. This design provides favorable gear tooth geometry that helps eliminate localized stress and loading on the gear tooth end, providing enhanced strength and longer gear life. Frictional losses are also reduced in this gear design, allowing Mack axles to deliver up to 1.5% improved fuel efficiency.

“Low-traction situations can be a challenge for truck drivers, seriously impacting their productivity,” said Roy Horton, Mack Trucks director of product strategy. “To help address that issue, we offer standard inter-axle and optional inter-wheel power dividers that automatically distribute torque between the slipping and non-slipping axle or wheel respectively.”

The axles also feature a top-mounted carrier design that is not only less prone to main seal leaks, but also provides more than two inches of additional ground clearance. An additional benefit of Mack’s top-mounted carrier design is improved driveline angles between the drive axles. Instead of a three and a half to eight-degree angle, Mack’s prop shaft angle is just one to two degrees. This maximizes universal joint life, allows for greater axle articulation and reduces vibrations for a smoother ride. It also reduces torque losses for improved efficiency.

The new rating comes as Mack celebrates 120 years of drive axle design, engineering and manufacturing this year. “Mack has a long and rich history of engineering and manufacturing its own powertrain components, including drive axles, as it fits with our philosophy that components designed to work together, simply work better,” said Horton. “We welcome the new S852, which will broaden the applications our trucks are built to handle.”