LISLE, Ill. — Navistar International Corp. announced on Monday that it has appointed Lewis B. Campbell executive chairman of the board of directors and interim CEO.

The appointment came after longtime leader Daniel C. Ustian informed the board that he was retiring as chairman, president and CEO, effective immediately.

"We appreciate Dan's many contributions and accomplishments during his 37-year career at Navistar,” said Michael Hammes, Navistar's independent lead director. “Under his leadership, Navistar's revenue grew from approximately $7.7 billion to approximately $14 billion as the company significantly expanded its global reach and diversified its product portfolio. ... We thank Dan for his dedicated service and wish him all the best in the future."

Also in the wake of Ustian’s departure, Navistar promoted Troy A. Clarke, the company’s president of truck and engine operations, to the position of president and chief operating officer.

Campbell is the former chairman, president and CEO of Textron Inc., a $12 billion publicly traded industrial company. He also has 24 years of experience in product design, engineering and manufacturing with General Motors.

"Lewis Campbell is a high-caliber executive who brings to Navistar deep and broad strategic, technical and operational skills and a proven track record of leadership with global industrial companies," Hammes said.

Prior to Clarke’s appointment as president of truck and engine operations at Navistar, he served as president of the company's Asia Pacific operations. He joined Navistar in January 2010 as senior vice president, strategic initiatives. Like Campbell, Clarke previously had a long career — 35 years — with General Motors in a variety of roles.

Clarke’s promotion at Navistar comes "in recognition of the significant contributions he has made in challenging assignments since joining the company in early 2010,” Hammes said. “Our board and management are aligned around a clear path forward, and we are confident that under the leadership of Lewis and Troy, Navistar will make continuing progress in executing its near-term strategic priorities, driving growth and creating shareholder value."

Officials said that the company will later conduct a search for a long-term CEO with internal and external candidates.