U.S. sales of medium- and heavy-duty trucks slipped 2.2% on a daily-selling rate basis in January compared with year-ago.

However, big-truck deliveries rose 1.8% on a volume basis to 24,921 units, WardsAuto data shows.

Class 8 led the month’s decline, with group sales falling 10.5%. PACCAR and Volvo Truck both saw losses, but International suffered the most severe falloff, down 44.3%. Daimler’s Western Star was the most improved, up 42.2%, although on the segment’s smallest volume of just 317 units.

Medium-duty sales somewhat balanced the Class 8 drop, rising 9.1% from prior-year, with all but Class 5 in the black.

Class 7 deliveries saw a 1.7% uptick in January, as segment-leading Freightliner, up 34.8%, and Hino, up 28.7%, tempered losses at UD Trucks, PACCAR and International. PACCAR’s Peterbilt brand tumbled the farthest, down 43.1% from like-2012.

Class 6 sales climbed 25.8%, with half of the manufacturers posting increases, including Ford, up 508.7% on 894 units, compared with 141 year-ago. PACCAR’s Peterbilt again fell the furthest, down 52.0% from year-ago but on minor volume.

Class 5 January deliveries slipped 4.2% from prior-year. Ford strengthened its hold on the segment, jumping 22% to 2,534 units, while Daimler’s Mitsubishi Fuso enjoyed the biggest gain, up 97.1% to just 39. Chrysler sales plummeted 65.5%, marking the biggest loss.

Class 4 sales soared 65.8% in the month for the best performance among medium-duty groups. Isuzu’s domestically built models spiked 115.2%. Ford helped with 151 deliveries, up 11 units from prior-year and good for 23.2% segment share.

Class 8 had a 62 days’ supply at the end of January, compared with 59 year-ago. However, inventory fell to 32,839 units from 34,751. There was a 76 days’ supply of medium-duty trucks, down from 82 prior-year, but the month’s inventory inched up to 35,666 trucks from 35,161.

In other big-truck news, Daimler Trucks North America reportedly could lay off as many as 1,500 workers, after hiring 1,400 in 2011 due to an improving economy. The company blames falling demand for its trucks resulting from the slowing economy.

Conflicting reports say 250 employees of Daimler’s Swan Island Western Star plant in Portland, OR, will be eliminated effective Feb. 15 or may be laid off by late February.

More than 1,000 jobs could be lost by April at Daimler’s Freightliner manufacturing operations in North Carolina if measures are not taken to address falling demand, the News Observer.com says. Citing a notice sent by Daimler to the North Carolina Commerce Dept., the report says 715 jobs are at risk at the truck maker’s Cleveland plant, 400 at Mount Holly and 85 at Gastonia.