GM's sales rose 2.6 percent over June and 5 percent from July of last year, helped by promotions to make room for 2011 models.
GM says sales from its four brands Chevrolet, Buick, GMC and Cadillac jumped 25 percent over July of 2009. Buick and Cadillac sales more than doubled. GM's total sales include Pontiac, Saturn and Hummer, which are brands it has sold or is discontinuing.
Newly launched models continue to propel GM's sales, with the Chevrolet Camaro muscle car, Chevrolet Equinox crossover, Buick LaCrosse sedan and Cadillac SRX crossover showing strong increases, the company said.
Ford, which has enjoyed a strong 2010 so far, said its sales were flat from June. They rose 3 percent compared with July last year, lifted by stronger sales of its Ford-brand cars and trucks.
Ford's overall sales were weighed down by a drop in Mercury sales. Ford will end production of that brand at the end of this year. Sales at its Lincoln luxury brand slid 16 percent, largely because of falling demand for the Town Car sedan, which will go out of production next year.
Industry analysts expected buyers to respond to the usual model year-end promotions advertised in July.
"Consumers have been conditioned to think that the summer is a great time to pick up a deal on a new car," Edmunds.com senior analyst Jessica Caldwell said.
Credit is also thawing, with auto loan approvals up for buyers in every tier. GM announced last month that it would buy AmeriCredit Corp. in an effort to expand loans to customers with poor credit and offer more leases.
But the market is still vulnerable. Auto sales have been recovering from a 30-year low in 2009, but the pace has been fitful, with month-to-month sales falling as often as they rose in the first six months of this year.
Most automakers saw sales fall from May to June as shoppers avoided showrooms due to economic worries. Americans' confidence in the economy eroded further in July amid worries about a still-stagnant job market, according to a report issued last week by the private Conference Board.
J.D. Power revised its full-year industry sales downward last week, to 11.7 million vehicles from 11.8 million vehicles, citing the inconsistent recovery.
Government stimulus efforts and businesses rebuilding inventory had been fueling the economic recovery, but those have run their course, and any second-half recovery in the auto industry now depends on consumer spending, said Ted Chu, GM's chief economist.
He said as long as employment continues to slowly improve and gas prices stay below $3 per gallon, sales should rise on a gradual basis.
"As long as the economy is slowly recovering back, I think pent-up demand is going to continue to be the driver," he said.
Automakers are also continuing to limit deals, which have hurt profits in the past. TrueCar.com estimated that incentive spending, at an average of $2,831 per vehicle, was down 1 percent industrywide from June.
Jeff Schuster, director of global forecasting at J.D. Power and Associates, said the sales pace dropped off in the last half of July, likely because of the lack of big incentives.
All automakers report U.S. July sales on Tuesday. Analysts expect the month to be one of the year's strongest and better than last July, when the government started its Cash for Clunkers rebate program to resuscitate depressed sales in the first half of last year.
Other automakers are reporting sales throughout the day:
Hyundai sales rose 6 percent from June. Sales climbed 19 percent from July 2009, lifted by brisk sales of midsize and smaller sedans such as the Sonata and Elantra. .
Kia sales rose 11 percent from June. Sales jumped 21 percent from July 2009, helped by new automobiles such as the Sorento crossover and the Soul hatchback.
Subaru sales rose 11 percent compared with June. Sales rose 10 percent from July 2009, with the Outback crossover leading the pack.
Daimler AG sales slipped 5 percent from June. Compared with July 2009, sales rose 7 percent, as strong sales of its Mercedes-Benz luxury cars offset plunging interest in its smart brand.