General Motors ( GM) said Monday that its new labor agreement with the United Auto Workers will pass an estimated $46.7 billion in retiree health care liabilities to the union, leaving the automaker with $17.6 billion in obligations. The historic agreement, ratified by UAW members in a vote held last week, will set up a union-controlled health care trust fund, dubbed a VEBA, that will free GM from the crushing burden of its long-term health care obligations to its workers in 2010. It also set up a two-tier wage structure that allows the company to pay new hires at lower rates. GM, which detailed the agreement on a conference call with analysts Monday, said the pact "significantly reduces GM's manufacturing cost gap to competitors." Shares of GM were recently trading down $1.34, or 3.1%, to $41.30. The stock gained 12% last week, crossing the $40-mark for the first time in about three years, as investors contemplated the implications of the agreement. Shares of Ford ( F) were down 17 cents, or 1.8%, to $9.03. Investors are expecting the No. 2 U.S. automaker to negotiate its own labor agreement with the UAW soon. Chrysler, which was recently taken private by Cerberus Capital Management, reached its own agreement with the union last week. Details of that deal are still emerging.