Featured MIPS Project: Improved Reliability in Truck Powertrains with Mack Trucks

Mack Trucks

Business Description

Mack engines are designed and manufactured at the company’s 1.5 million-square-foot facility in Hagerstown, Md. The TC15 transfer case, rear engine power take-off and Mack Maxitorque ES T300 series transmissions are also produced there.


Mack Trucks sought to improve the reliability of valve lifters used in the company’s engines.


The project team tested two types of valve lifters: brazed lifters in current use and a newly designed HIP-bonded lifter (a hot-isostatic pressed design). Through engineering analysis and testing, UMD researchers determined that the HIP-bonded lifter would provide a 5x improvement in durability over the older-style brazed lifter. UMD researchers also discovered that the as-built HIP-bonded lifters had an unacceptably thin carbide layer. Finally, the team devised an ultrasonic inspection method for the new lifters.

Mack Trucks


As a result of this project, Mack switched entirely from brazed to HIP-bonded lifters. The company also instituted manufacturing controls to ensure proper thickness of the carbide layer on the HIP-bonded lifters. This dramatically improved their powertrains’ reliability, which led to savings in warranty costs, an improved market share and the creation of new jobs in Hagerstown.

Interesting Fact

Mack Trucks in Hagerstown is now Volvo Powertrain North America, a division of Volvo.


“We believe that this has already started to contribute to our recent increase in market share, and expect it to be an important factor in further increases.”
–Brad Toole, Engineering, Mack Trucks

Project Manager:  Brad P. Toole;  Principal Investigator:  Robert J. Sanford, UMD
Location:  Hagerstown, Maryland – Washington County

Mack Trucks

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