DaimlerChrysler's Detroit Diesel Corp. said it plans to lay off up to 700 workers at its Redford, MI on-highway engine plant in October due to slow orders for its new low-emissions engines. Between 500 to 700 workers will be idled for an indefinite time by the second week of October because orders for Series 60 engines fell, spokesman Tom Freiwald said. DaimlerChrysler expects to recall them when demand returns, he said. "There's no way that these would be outright firings, since those workers have recall rights," said Sean McAlinden, a labor consultant for the Center for Automotive Research in Ann Arbor, who has done work for the United Auto Workers union, told Bloomberg News. Engine production will decline to 50 to 60 engines daily in October from about 250 a day now, Freiwald said. Fleets have been pre-buying trucks to beat the October 1 deadline and avoid the new technology. Fleets are concerned that the engines have not been adequately field-tested. Analysts said North American heavy-truck orders rose 61% through July from a year earlier because of the pre-buying.