All truck manufacturers showed double-digit gains for Class 8 truck sales last month, according to WardsAuto.Class 8 sales were up 30.4% overall, with Daimler brands Western Star in the lead and Freightliner posting a 32.9% increase. PACCAR Kenworth’s sales were up 31.5%, Peterbilt came in with a 37.2% increase, and Volvo and Mack posted increases of 19.6% and 35.5%, respectively. In addition, medium-duty sales were up 18.5% last month compared to what they were in March, 2014.All weight classes saw year-over-year increases in March, according to the report, and last month was the industry’s 19th consecutive month of year-over-year gains for medium- and heavy-duty trucks.