Philip J. Christman has served as a director of Allison Transmission Holdings, Inc. since August 2022. Mr. Christman recently retired as President, Operations of Navistar, Inc., a leading manufacturer of commercial trucks, buses and engines, a role he held from May 2017 until March 2022. In this role, he was responsible for all Navistar operations encompassing engineering, manufacturing, procurement and quality. He began his career with Navistar in 1986 and held various management positions of increasing responsibility in operations, engineering, procurement and strategy. Mr. Christman has a Bachelor of Science degree in Mechanical Engineering from Indiana Institute of Technology and a Master of Business Administration from Ball State University.