Sales in Class 8 trucks continued to climb last month, lifting the overall market according to WardsAuto.Class 8 sales were up 15.4% at 20,509 units compared to 17,776 a year-ago, as all companies posted gains except for International, according to the report. Daimler brands Western Star (+45.7) led all gainers, while Freightliner posted a 9.1% increase. PACCAR’s Kenworth was up 31% and Peterbilt jumped 36.4%, WardsAuto said. Volvo truck brands Volvo and Mack recorded increases of 18.7% and 6.6%, respectively, according to the report.Medium-duty sales dropped 10.3% last month compared to 15,696 units delivered in 2014.WardsAuto also reported that Canada saw its eighth consecutive month in year-over-year increases in big truck sales. According to the report, Canada had its best April since 2008 with deliveries at 4,037 units compared to 3,765 last year.Class 8 sales rose 2% to 2,610 units, while Class 7 sales soared by 20.1%.