DETROIT (AP) — U.S. sales of new cars and trucks were expected to drop in August, ending summer on a low note for the auto industry.

General Motors' sales dropped 5 percent from last August while Ford's sales were down 8 percent. Nissan's sales dropped 6.5 percent.

Other automakers will report sales later Thursday.

Overall industry sales were expected to slip 5 percent to 1.5 million vehicles, according to J.D. Power and LMC Automotive. If that happens, it would be the fourth month this year that sales have been flat or have declined on a year-over-year basis. Total sales through August are now expected to be flat compared to a year ago.

This isn't unexpected. After six straight years of growth — and record sales of 17.5 million new vehicles last year — the industry has been bracing for a plateau as consumer demand wanes.

Demand is softening despite model year-end clearance sales, low gas prices, low interest rates and other enticements. LMC Automotive forecasting chief Jeff Schuster now thinks it will be increasingly difficult for the industry to match last year's performance.

"With mixed economic signals, it certainly looks like U.S. auto sales may have peaked in 2015," Schuster said.

That's good news for consumers, who can expect automakers to raise incentive levels in the coming months. But the industry will need to be careful, since incentives ultimately erode profits and resale values.

General Motors Co. said its Cadillac sales grew 4 percent in August, thanks in part to its new CT6 sedan and XT5 SUV. But it Buick, Chevrolet and GMC sales fell, and its overall sales dropped 5 percent to 256,429 vehicles. Sales of GM's best-seller, the Chevrolet Silverado pickup, dropped 5 percent. GM has cut back sharply on low-profit sales to rental car companies, which accounts for some of the losses. GM says its rental sales are down 34 percent so far this year.

Ford Motor Co. said its Ford brand sales were down 9 percent while its Lincoln brand sales rose 7 percent thanks to its new MKX SUV. Ford's overall sales fell 8 percent to 214,482. Ford's best-seller, the F-Series pickup, saw a 6-percent sales decline as the company prepares to launch new heavy-duty trucks. Ford reported a whopping 27 percent decline in car sales, reflecting buyers' overwhelming preference for SUVs.

Nissan Motor Co. said its sales fell 6.5 percent to 124,638. Infiniti sales were down 2 percent but Nissan brand sales fell 7 percent. SUV demand remained strong; Rogue small SUV sales were up 19 percent.