Franchised dealers of U.S. truck manufacturers sold 706,440 units in March 2002, according to data published by Ward's Communications. Retail sales for March ran 6.7% below sales for the month a year ago. The biggest drop: Class 4 was down 40.4%. The biggest gain: Class 3 was up 65.5%.Visit http://www.ntea.com/MarketData/truck_sales.asp to view the latest numbers, plus a five-year sales history for all truck classes.