(Updates with additional commentary, Toyota sales, GM estimates, background)
By Nick Carey
DETROIT, Aug 1 (Reuters) - Major automakers on Wednesday reported lower U.S. new vehicle sales for July amid steep declines in passenger cars, except Fiat Chrysler Automobiles NV (FCA) , which said its sales climbed 6 percent.
U.S. consumers have been shifting away from traditional passenger cars in favor of larger, more comfortable SUVs and pickup trucks, which are also more profitable for automakers.
"Every year there is a clunker of a month," Mike Jackson, chief executive of AutoNation Inc, the largest U.S. auto retail chain, told Reuters. "I think July will be that month from a retail point of view."
U.S. new vehicle sales rose in the first half of 2018, boosted in part by an overhaul of the tax system, but are expected to fall in the second half amid rising interest rates and a glut of cheaper, nearly-new used vehicles.
U.S. auto sales fell 2 percent last year after hitting a record high in 2017. Full-year 2018 sales are expected to be lower than last year's.
FCA's rise in July sales was due mostly to higher sales to consumers, above all a 15-percent jump in sales of its popular high-margin Jeep brand.
Sales at Ford Motor Co slipped 3.1 percent for July. Ford's retail sales sank 10.4 percent, largely due to a 28 percent slump in passenger cars.
But sales of Ford's high-margin pickup trucks jumped 10.2 percent.
The No. 2 U.S. automaker said earlier this year it would gradually cease production of most passenger cars in the United States. On a conference call, U.S. sales chief Mark LaNeve said Ford had ended production of its Focus sedan and was winding down output of the Fiesta.
Toyota Motor Corp reported an overall drop in sales of 6 percent for the month, with U.S. passenger car sales down 16.5 percent and pickup truck and SUV sales up 2.2 percent.
Earlier this year, General Motors Co stopped reporting monthly sales and switched to reporting them quarterly. The No. 1 U.S. automaker's sales were expected to be down slightly over 2 percent for July.
At Nissan Motor Co Ltd, vehicle sales fell 15.2 percent in July. Passenger car sales were down 21.1 percent, SUV and pickup truck sales fell 10.6 percent.
Nissan "experienced some challenges" in July, but made progress towards "sustainable retail growth," said Billy Hayes, the automaker's vice president for regional operations in North America.
Nissan has worked to smooth its transition to the 2019 model year so it does not end up stuck with old models and has worked to reduce its inventory, Hayes said.
"It seems like it (July) was tough across the board, across the industry," Hayes said. "It seemed to impact us all."
Honda Motor Co Ltd's July sales were down 8.2 percent. Its passenger car sales were off 19.3 percent, while sales of its SUVs rose 3.2 percent.
Ford shares dipped 0.8 percent in morning trading, while FCA's shares fell 1.4 percent.
Last week, Detroit's automakers warned that mounting U.S. and Chinese tariffs would hurt their results in 2018.
U.S. President Donald Trump agreed last week after meeting with European Union officials to refrain from imposing car tariffs while the two sides launch negotiations to cut other trade barriers, easing the threat of a transatlantic trade war.
But the possibility that Trump might reverse course impose broader tariffs is still a cause for concern in the industry.
"The whole trade war and tariffs are deeply unsettling from an economic point of view, AutoNation CEO Jackson said. "The threats of tariffs on motor vehicles is a great concern."
"It will make the other tariffs look like a company picnic."
Reporting By Nick Carey Editing by Bernadette Baum and Alistair Bell