WASHINGTON — Humbled and fighting for survival, Detroit's once-mighty automakers appealed to Congress with a retooled case for a bailout as large as $34 billion Tuesday, pledging to slash workers, car lines and executive pay in return for a federal lifeline.

GM and Chrysler said they needed an immediate cash infusion to last until New Year's and warned they could drag the entire industry down if they fail.

Chrysler LLC said it needed $7 billion by year's end, and General Motors Corp. asked for a quick $4 billion as just the first installment of as much as $18 billion to stay afloat and weather even worse economic storms. Ford Motor Co. had a more upbeat report, but the other two members of the U.S. Big Three painted the direst portraits to date — including the prospects of shuttered factories and massive job losses — of what could happen if Congress doesn't quickly step in.

"Failing to act now will hurt many American families and undermine our country's economic recovery, far outweighing the costs related to supporting an industry that touches every district in every state of the nation," Chrysler said.

"There isn't a Plan B," said GM Chief Operating Officer Fritz Henderson. "Absent support, frankly, the company just can't fund its operations."

New sales figures underscored the seriousness of the situation.

U.S. light vehicle sales at General Motors and Chrysler plunged more than 40 percent in November, while Ford's sales dropped 31 percent, battered by an economic storm that has sent consumer demand for new vehicles to lows not seen in decades.

"Our industry is in a much more severe situation than the rest of the economy," said Mike DiGiovanni, General Motors Corp.'s executive director of global market and industry analysis. "We cannot continue at these levels or else the entire industry is going to go down."

U.S. auto sales in November fell to 746,789, according to Autodata Corp. On a seasonally adjusted basis, automakers reported an annual sales rate of 10.2 million units, the lowest level since October 1982.

Automakers and analysts blamed the crumbling economy, less access to vehicle financing, and a wait-and-see approach among consumers more preoccupied with the value of their homes and the fate of their jobs than the lure of a new car.

"Consumers (are) not showing up at the dealerships — regardless of the deals they're being offered and regardless of how low the gas prices go," said Jesse Toprak, executive director of industry analysis for the automotive Web site Edmunds.com.