Sales of medium- and heavy-duty trucks in Canada fell 11.7% on a daily basis from year-ago in July, WardsAuto data shows, as just one weight class posted a strong increase.

Class 6 sales grew a leading 19.5%, although Class 7 also made it into the black for the month, up a scant 0.7%.

Class 8 suffered the biggest decline, down 16.3%, due to losses posted by most of the group’s manufacturers, including a 41.6% plunge by a still-struggling International.

The only Class 8 gainer was Volvo Truck, whose Mack Truck operation recorded a 9.5% rise that offset a 5.4% drop for the Volvo brand.

Total medium-duty sales slipped 0.5%, due to declines in Classes 4 and 5.

Class 7’s slight rise was driven by 20%-plus gains at Hino and International. Ford posted the segment’s biggest increase, up 44.0% daily, but on minor volume.

The Blue Oval brand’s 36 units drove the Class 6 July uptick and secured the No.2 spot for Ford, which was dead last in the segment year-ago.

International’s 1.6% gain also contributed to Class 6’s positive results, while Freightliner and PACCAR each saw daily sales slip 4.0% from year-ago.

Class 5 sales slipped 3.6% last month, as double-digit percentage gains at Isuzu (40.0%), International (34.0%) and Chrysler (25.9%) couldn’t offset underwhelming results for Daimler, Ford and Hino. Daimler’s 47.2% decline was the biggest in Class 5.

Hino was the leading gainer in Class 4, up 130.4%, but that wasn’t enough to prevent the group from sliding 13.1% in July, as all other manufacturers fell into the red.

With July’s decline, Canada’s big-truck market continued to struggle, with 7-month sales off 10.3% from year-ago to 23,629 units.