Orders of medium-duty vehicles in Classes 5-7 increased 1% to 15,344 in July, while Class 8 orders declined 58% to 10,358, according to ACT Research.

Medium-duty orders also increased 1% over July of 2015.

A steady-as-she-goes sentiment remains in place for medium-duty vehicle markets, said Kenny Vieth, president and senior analyst for the firm.

"After an eight-month run in which Classes 5-7 orders averaged 21,300 units per month, driven in part by new product introductions, orders have cooled," Vieth said. "In July, total Classes 5-7 net orders rose, with seasonal adjustment boosting the total to 18,200 units."