But full-year sales at Ford and General Motors lagged. Ford edged up 5 percent and GM rose only 3.7 percent for the year. For December, Ford was up 2 percent and GM up 5 percent.
GM executives said the company has the oldest model lineup in the industry, yet it still posted a sales increase and commanded high prices for cars and trucks. The company plans to refurbish 70 percent of its North American models in the next 18 months and expects to boost sales this year.
North American President Mark Reuss said the company won't give away cars and trucks with discounts like it has in the past, especially in the midst of its biggest product update ever.
"Give us 18 months and you're going to see the whole portfolio turned," Reuss said.
Even though the congressional deal to avoid the fiscal cliff deal raised tax rates on the wealthiest Americans, Ford said it doesn't see a huge impact on auto sales.
Its chief economist, Ellen Hughes-Cromwick, said only 2 percent of new-vehicle buyers have income in that upper tax bracket, and they tend to purchase even if there is a change in after-tax income.
She said Ford is more concerned about an increase in the payroll tax, which is scheduled to climb to 6.2 percent this year from 4.2 percent in 2011 and 2012. That amounts to a $1,000 to $1,500 tax increase per household, she said.
"We will look at that closely because it will crimp spending in the months ahead," she said.
December featured year-end deals on GM's big pickup trucks. The company offered discounts up to $9,000 to help clear growing inventory, and it worked. GM cut its full-size pickup supply by more than 20,000 in December to about 222,000.
Overall, though, analysts said the industry eased up on promotions such as rebates and low-interest financing. Car and truck buyers paid an average of $31,228 per vehicle last month, up 1.8 percent from December 2011.
The Polk auto research firm predicted even stronger U.S. sales for 2013, forecasting 15.3 million vehicle sales as the economy continues to improve. Polk, based in Southfield, Mich., expects 43 new models to be introduced, up 50 percent from last year. New models usually boost sales.
The firm also predicts a rebound in sales of large pickups and midsize cars. All eight of the top manufacturers are introducing new vehicles, and that should bring competition and lower prices in those segments, according to Tom Libby, lead North American analyst for Polk.But the firm's optimistic forecasts hinge on Washington reaching an agreement on government debt limits and spending cuts.