America's resurgent housing market, along with strong demand from the booming energy sector, are pushing pickup truck sales to their strongest levels in six years.
"We are seeing a lot of increased business primarily due to the increases in housing. Availability of consumer credit is obviously not hurting us either," said Kurt McNeil, Vice President of U.S. sales for General Motors. "The housing and the truck sales have sort of lead, but we are seeing the American family coming back now too with pretty good crossover and utility sales."
Overall, the large full-size market is expected to make up 11.5 percent of all auto sales last month, an increase of 1 percent compared to the same period in the last 3 years.
The strength in pickups is one reason May sales are slightly higher than estimates.
Ford's F-Series, the top-selling vehicle in the U.S., posted its strongest May sales since 2005. Ford sold 71,604 F-Series trucks last month (up 30.6 percent) and has sold almost 300,000 F-series this year, an increase of 21.7 percent.
As has been the case in recent months Ford saw strong demand for new trucks from contractors in the recovering housing market, but also experienced sales growth from the booming energy sector in the United States.
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"I was just down in Houston and it's running very strong," said Ken Czubay, Ford Vice President of U.S. Marketing. "At the same time, when we look at areas in West Texas, the northern plains, the Dakotas and even Pennsylvania where fracking is big, we're also seeing big demand for the F-series."
Small Business: Restocking Fleets
General Motors said much of what's driving demand for the Chevy Silverado and GMC Sierra is the return of small business owners buying or replacing a single or several work trucks.
"We're seeing service businesses, landscape companies and contractors. These are the folks coming in right now to buy one to four new trucks," said Ed Peeper, Vice President of Fleet and Commercial sales with General Motors.
(Read More: Ford Putting the Pedal to the Medal)
Incentives for both GM and Ford were relatively in check last month. GM said its trucks incentives dropped $300 compared to the same month last year, while Ford says F-series incentives increased by $400. Ford said the average truck incentive was $4,700.
—By CNBC's Phil LeBeau. Follow him on Twitter
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