Continuing this year’s trend, sales of medium- and heavy-duty trucks in Canada declined in May, down 5.4% as Classes 4, 6 and 8 lost volume from year-ago.

Class 8 deliveries dropped 14.0% as PACCAR’s Kenworth, one of the group’s mid-volume players, tumbled 38.9%, WardsAuto data shows.

Other manufacturers in the group saw losses. Only the Volvo Truck brand and Daimler’s Western Star were in the black, up 5.0% and 2.0%, respectively.

Total medium-duty sales climbed 14.1% in May, with Class 7 posting the heftiest jump, up 22.6%.  Daimler’s Freightliner more than doubled its year-ago volume, spiking 116.7%. All brands gained volume in Class 7 last month except for PACCAR’s Peterbilt, down 3.6%, and Hino, falling 13.9%.

Class 6 deliveries were flat, down 0.6%, in May. A 130.8% jump at Freightliner couldn’t offset losses at most of the group’s other manufacturers, including 80.0%-plus declines at PACCAR and Ford.

Chrysler and Isuzu enjoyed gains exceeding 60% in Class 5, giving the segment a 21.9% boost from prior-year.

Chrysler sold 239 units in Canada’s Class 5 in May, up 66.0% from 144 year-ago, placing the truck maker second in volume to Ford. Daimler’s Mitsubishi Fuso plunged 66.7%, making it the weakest performer in Class 5.

Deliveries of Isuzu’s domestically built models soared 90.9% in Class 4. However, the group fell 14.8% off its year-ago pace. Ford dropped 26.1% while Isuzu’s imported models saw a 57.1% falloff of just nine units compared with 21 year-ago.

Through May, sales of medium- and heavy-duty trucks were down 9.8%, to 16,860 units, compared with 18,688 in like-2012.