General Motors' July sales fell 6 percent from a year earlier, while Ford's slipped 4 percent. By contrast, Toyota posted a 26-percent jump and Nissan's sales rose 16 percent. GM blamed the decline on a planned drop in sales to rental car companies, but its retail sales to individual buyers also fell.
Industry sales overall are expected to rise 11 percent for July, boosted by summer clearance deals and low-cost financing. Analysts predict big gains for the Japanese, which couldn't supply enough models to U.S showrooms last summer after production was hobbled by Japan's earthquake.
Automakers are reporting U.S. sales throughout Wednesday.
The third big U.S. automaker, Chrysler, had better news. It had its best July in five years, as sales rose 13 percent, led by strong demand for its Ram pickup and Chrysler 200 sedan. Volkswagen continued its strong growth, too, as sales rose 27 percent.
Car shoppers had a lot to like last month, analysts say. There were good deals on last year's models, low- or no-interest financing and strong trade-in values due to high used-car prices. That helped buyers shrug off negatives such as stagnant hiring and the financial crisis in Europe.
Auto loans are available from banks for just over 3 percent, and car companies are offering zero-percent financing on many models.
TrueCar estimates Volkswagen's incentive spending was up 38 percent last month. Volkswagen was offering zero percent financing for five years on all non-diesel 2012 models. Nissan's spending was also up 22 percent to $3,205, the highest level among the eight largest automakers. Nissan was offering up to $3,400 off the outgoing Altima sedan as the new version hits the market.
At Ford, the Lincoln luxury brand and Fiesta subcompact dragged down sales. Lincoln sales dropped 11 percent, while the Fiesta was off 23 percent. Sales of the Escape small SUV fell 12 percent after the latest version was recalled for safety problems.
Ford's best performer in July was the Fusion sedan, which saw sales climb 21 percent. The Ford Explorer SUV was up 14 percent.
At GM, only the Cadillac brand reported a sales increase, up almost 21 percent. Sales of the Chevrolet Cruze compact fell 39 percent as Honda and Toyota had full supplies of small cars. The Cruze was the top-selling compact in the nation a year ago when Honda and Toyota supplies were short.
At Chrysler, sales of its best-selling Ram pickup rose 17 percent in July as home building increased. And the company's highly-anticipated new car, the Dodge Dart, saw sales hit 800.
Sales of the Chrysler 200 jumped 43 percent. The 200, formerly called the Sebring, was revamped last year and got a huge boost after being featured in a 2011 Super Bowl ad with Detroit rapper Eminem and a tagline of "Imported from Detroit."
There are signs, though, that Chrysler won't be able to keep up the blistering growth pace from earlier in the year. The company's sales grew more than 30 percent in the first half, and were up more than 40 percent in January and February.
Nissan's sales increase was led by the Infiniti luxury brand, which was up 57 percent. Volkswagen had its best July since 1973, led by the new Passat midsize sedan.