General Motors workers return to work today after the auto maker agreed to a new labor contract with the United Auto Workers union. The deal ends a two-day strike but questions remain just how much the deal will save GM.

Shares of GM rose $2.76, or 8.0%, to $37.18, after the company agreed to a tentative contract with the UAW. The UAW represents approximately 74,000 GM employees. The contract ends a national strike that began Monday and crippled GM's production.

The deal sets up a health care trust to pay for retiree healthcare benefits. GM will front the money for the trust while the UAW will run it. GM hopes the trust will help it close a $25-per-hour labor gap with foreign auto makers.

"This agreement helps us close the fundamental competitive gaps that exist in our business," said GM Chief Executive Rick Wagoner. "The projected competitive improvements in this agreement will allow us to maintain a strong manufacturing presence in the United States along with significant future investments."

But former Forbes senior editor Jerry Flint says that the health care trust won't reduce any costs. He explains the health care bill remains the same whether the UAW or GM is in charge. "A health care trust, if it happens, may look good today, but one day it will come back to haunt GM," says Flint.

The deal must now be approved by the rank-and-file union membership. The Securities and Exchange Commission must also review the contract.