DETROIT — The United Auto Workers said early today it has reached a tentative contract agreement with General Motors Corp. that ends a two-day nationwide strike.

The union said the deal was reached shortly after 3 a.m. and that workers would be encouraged to go back to work immediately.

A person briefed on the contract told The Associated Press earlier that the agreement would shift the burden of retiree healthcare from GM to the union and give workers bonuses and lump-sum payments. The person requested anonymity because the contract talks are private.

The contract must be reviewed by local UAW presidents and will then be subject to a vote of GM's 73,000 rank-and-file members. The agreement is expected to set a pattern for contracts at Ford Motor Co. and Chrysler LLC.

The union said it went on strike largely because GM failed to make promises for future products and investment in U.S. plants. GM said it was disappointed and would work with the UAW to address its competitive challenges.

The strike had an impact at non-UAW-represented GM plants and at suppliers.

Yesterday, GM idled two car assembly lines employing about 5,600 people at its plant in Oshawa, Ontario. On Monday, it idled a transmission plant in Windsor, Ontario, that employs 1,300. Workers at both are represented by the Canadian Auto Workers union.

Parts shortages forced GM to cancel one shift yesterday at a Moraine, Ohio, assembly plant that makes sport utility vehicles. The plant's 2,300 workers are represented by the International Union of Electronic Workers-Communication Workers.

Delphi Corp., GM's largest supplier, said yesterday it was temporarily laying off workers. Spokesman Lindsey Williams wouldn't give numbers because the situation was in flux. Delphi has about 25 U.S. plants that supply parts for GM.

Last night, picketers remained at the GM factories and other facilities, although several industry analysts had expected the walkout to be short.

A 1970 strike against GM went on for 69 days and helped push the nation into a recession, but industry watchers didn't think that would happen this time.

Both sides had something the other desired — the workers wanted job security, GM wanted the union to take on the burden of retiree healthcare — and that's the stuff that agreements are made of.

"The UAW and GM understand that a strike is a lose/lose proposition," Deutsche Bank analyst Rod Lache said yesterday in a note to investors.

Talks broke off Monday when the strike began, but resumed in the afternoon and continued into the evening when weary bargainers broke for a rest. Analysts were encouraged that the talks continued throughout the strike.

The union said it went on strike largely because GM failed to make promises for future products and investment in U.S. plants. GM said it was disappointed and would work with the UAW to address its competitive challenges.

"I'm hoping we get a fair contract. I understand that General Motors has their back against a wall. But I don't want to give them everything," said autoworker Ernie Bruton, who was picketing yesterday outside a GM engine plant in the Detroit suburb of Romulus.

Wall Street took a wait-and-see approach. GM shares slipped 32 cents, or less than 1 percent, to close at $34.42 yesterday.

In 1970, the UAW's strike against GM rippled through the economy. Production declined, unemployment rose and retail auto sales dried up, according to an analysis by Merrill Lynch. A 54-day strike against two GM plants in 1998 wreaked similar havoc and cost GM $2.2 billion.

The retiree healthcare trust could save GM an estimated $3 billion per year, Lache said, making it more competitive with Asian automakers who have fewer U.S. retirees and insulating it from healthcare inflation. UAW President Ron Gettelfinger said Monday the union is considering the trust, called a Voluntary Employees Beneficiary Association, or VEBA.

GM has $51 billion in unfunded retiree healthcare liabilities. Lache said GM didn't want to put more than 65 percent of that total into the VEBA but may have agreed to a higher percentage to appease the UAW. If so, the automaker must now hold the line on job security and wages. Lache predicted that UAW will eventually accept a lower number on the VEBA in order to extract other promises from GM.

The union's quest to preserve jobs through guarantees that new cars and trucks will be built at U.S. factories clashes with GM's need to close plants to match demand for its products, said Greg Gardner, an analyst for Harbour Consulting, a Troy company that tracks manufacturing productivity.

Most of the discussion probably centered on plants that build small- and mid-size cars such as Lordstown, Ohio; Kansas City, Kan.; and Orion Township, Mich., Gardner said.

The profit margins on those vehicles are so slim that it makes more business sense to produce them in places with lower labor costs, like Mexico, said Erich Merkle, vice president of auto industry forecasting for consulting company IRN Inc. in Grand Rapids.

GM needs the flexibility to close plants when demand for a certain product drops, Gardner said. Currently the company must pay workers most of their wages when they are laid off.

Many analysts expected the automaker to make concessions in order to get the VEBA. "It won't be everything GM is looking for. They'll have to agree to building a cost-efficient product in a UAW plant," said James Hendricks, a partner with the labor and employment law firm Ford & Harrison.