Detroit Diesel Corp. (DDC) said it would follow through with plans to lay off between 500 and 700 workers and retool its manufacturing facility after it did not hear from a federal judge Monday. DDC had asked the court to allow it to continue producing and selling its traditional diesel engines after the October 1 EPA emissions deadline. Fleets are concerned that new EGR-equipped engines have not been adequately field-tested. However, by October 1, DDC said it will have accumulated approximately eight-million test miles on its fleet of test vehicles equipped with October 2002 prototype engines. Workers at its Redford, MI on-highway engine plant 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, DDC's parent company, expects to recall them when demand returns, he said. 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 thereby avoid the new technology.