Medium- and heavy-duty truck sales rose 27.8% in Canada in March, the 24th consecutive month of gains for the sector.

All but Classes 4 and 6 posted increases, WardsAuto data shows, with Class 8 up 42.7% from year-ago and Class 7 soaring 57.9%.

All Class 8 manufacturers were in positive territory in March, including Peterbilt, up 82.9%, the group’s biggest year-on-year rise. International’s 8.2% uptick marked the most modest gain in the group.

Due to the Class 4 and 6 declines, medium-duty sales rose just 4.3% in March.

Class 7’s nearly 60% spike was due entirely to demand for domestic models. Freightliner posted a 149.8% jump from year-ago and volume-leading International notched an 82.4% rise. Hino, down 1.8%, was the only Class 7 brand losing volume.

Class 6’s 34.6% slump was the worst among big-truck groups, as volume leaders International and Hino posted drops of 26.5% and 67.9%, respectively. PACCAR recorded a 285.7% increase on sales of just four units.

The situation was reversed in Class 5, with Hino (up 136.5%) and International (gaining 107.7%) driving the sector’s modest 8.4% rise, while PACCAR slid 72.4%.

Almost all manufacturers stumbled in Class 4, bringing about a 26.1% decline. Daimler’s 71.1% falloff was the biggest, but volume-leader Ford lost 24.8% of its year-ago volume. A 31.5% rise in sales of imported Isuzus marked the lone uptick in Class 4.

Through March, Canada big-truck sales were running 46.3% ahead of like-2011, totaling 10,466 units.