Overall, US auto sales are slowing after a long bull run that has satiated replacement demand.

In a significant development for the pickup truck segment, Fiat Chrysler Automobiles NV's (FCA) Ram pickup outsold General Motors Co's Chevrolet Silverado in the second quarter.

GM reports sales on a quarterly basis instead of each month.

The Silverado has long held second place behind Ford Motor Co's F-Series pickup trucks, with Ram often a distant third.

But for the first six months of 2019, FCA's sales of Ram pickups outpaced Chevy Silverado sales by more than 40,000 vehicles.

FCA, GM and Ford escalated a price war in June over pickup trucks - one of the few vehicle market segments that offers substantial profits, which matters at a time when overall US new vehicle sales are expected to fall this year.

High interest rates, plus competition from millions of nearly new, off-lease vehicles have translated into fewer consumers splurging on new cars.

After a weak start to the year, sales in the last couple of months have been largely flat versus 2018.

"The market is not as down as it was to start off the year, which says a lot about market stability," said George Augustaitis, director of industry analysis at CarGurus Inc , an online marketplace for new and used cars.

"At this point, a Fed interest rate cut could be the thing that sparks the industry."

FCA said its sales rose 2pc in June, driven by a 56pc jump in Ram sales.

GM said second-quarter sales fell 1.5pc, with strong sport utility vehicle sales offset by a poor performance for its pickup trucks.

The No. 1 US automaker said sales of its trucks would pick up in the third quarter as both its most popular and most affordable versions of the Silverado will hit dealer showrooms.

Toyota Motor Corp reported a 3.5pc drop in sales for June, led by falling sedan sales.

In the last few years, Americans have increasingly shunned passenger cars in favor of larger, more comfortable SUVs and pickup trucks.

Nissan Motor Co Ltd's sales plunged nearly 15pc, with huge drops for much of its lineup including the best-selling Rogue SUV.

After years of relying on steep discounts to increase US market share, Nissan is trying to pull back so it can sell vehicles more profitably.

Billy Hayes, Nissan's North American vice president for sales, said many of the automaker's models will be revamped in the next year or two, which will help lift sales.

"We're bullish on the market and we see positive conditions for our all-new models," he said. "We're working to win in the long term."

Hyundai Motor Co on Tuesday reported a 1.5pc rise in US sales for June, lifted by strong demand for SUVs and trucks.