Medium- and heavy-duty truck sales rose 5.2% in Canada in September.

The positive performance was driven by a 52.0% jump in Class 7 sales and smaller hikes in Classes 5 and 8, WardsAuto data shows.

Class 8 posted the smallest increase last month among the big-truck groups, inching up 1.1%, as a 32.4% decline in International sales and drops at PACCAR’s Kenworth and Volvo’s Mack Truck offset growth at most manufacturers.

Peterbilt notched the biggest Class-8 gain in September, up 33.3%.

Medium-duty sales rose 11.6%, on Class 7’s strong showing, which offset Class 4 and 6 losses. International posted the biggest increase by far in Class 7, up 81.0%. Freightliner sales fell 25.5%, pushing parent Daimler’s results down from year-ago by the same percentage.

Class 6’s 16.9% drop was due to losses at three of the four manufacturers in the sector. Ford slid 50.0%, Daimler 33.3% and International 17.1%. Only Hino posted an increase, up 13.6% over like-2011.

Despite declines for most of the segment’s manufacturers, Class 5 sales rose 3.5%. Hino’s 441.7% spike, on relatively low volume, and International’s 78.1% surge kept the group in the black. Ford, the Class 5 volume leader, saw sales fall 36.8% from year-ago.

Class 4 deliveries declined 7.0%, with all three players down at least 21%. Daimler posted the biggest falloff, with daily volume 28.6% below prior-year.

Through September, big-trucks sales in Canada are up 23.4% from year-ago to 33,853 units.