DETROIT (AP) _ General Motors Corp.'s labor relations chief Gary Cowger, credited with helping ease company tensions with the United Auto Workers, has been promoted to take over the company's massive North American manufacturing operations.

Cowger, 53, will assume responsibility for all manufacturing operations, assembly facilities, metal fabrication and labor relations in North America.

Cowger is credited with helping repair GM's strained union relations after a 1998 strike that lasted 54 days and cut profits by $1.9 billion. He'll take over for veteran executive Donald Hackworth, the former head of GM's car group.

Also Friday, GM announced the promotion of Thomas Davis, 49, to vice president of product development. Davis currently heads GM's truck group. He will now be responsible for GM's system of bringing vehicles from the design stage to production.

The promotions take affect in January. Davis and Cowger will report to Ronald Zarrella, executive vice president and president, GM North America.