"Over the past several months, the contraction of credit in the auto finance markets has helped driver our auto industry into a historic crisis," said Treasury Secretary Tim Geithner in a statement.

"This new arrangement with GMAC will help provide a reliable source of financing to both auto dealers and customers seeking to buy cars," Geithner said.

GMAC, the main source of financing for General Motors customers and was recently tapped by the U.S. government as the main lender for Chrysler LLC, had received about 6 billion dollars from the government.

The Treasury said the new injection will help provide a reliable source of financing to auto dealers and people looking to buy GM and Chrysler vehicles.

Geithner noted that the new help will "offer strong credit opportunities, help stabilize our auto financing market, and contribute to the overall economic recovery."