The head of the Canadian Auto Workers union expects to see a new contract proposal from General Motors and expressed optimism Tuesday that a tentative deal could be reached soon.

"The best thing I can say is we're having constructive discussions with General Motors today and there's a similar feeling of optimism at Chrysler at the subcommittee level, although there hasn't been a lot of work at the senior levels," CAW president Ken Lewenza told reporters.

Discussions with both automakers will continue through the night.

Lewenza told CBC News earlier that the union doesn't want to strike at Chrysler and GM, but it will if forced. He said there is too much at risk for the company and union. So he extended the negotiation deadline indefinitely.

“There’s a tremendous amount of momentum building for General Motors and Chrysler,” Lewenza said. “We don’t want to stop that momentum.”

Earlier this year, GM regained its crown as the world’s top-selling automaker, and Chrysler has posted 29 consecutive months of year-over-year sales gains through August.

Lewenza called Chrysler’s recovery “miraculous.”

It was business as usual Tuesday at the Big Three U.S. automakers across Ontario after the CAW reached a tentative four-year deal with Ford on Monday.

However, the risk of a strike at Chrysler and GM plants in Canada remains, the CAW has warned. Lewenza again Tuesday called a strike "the last tool in the toolbox."

Chrysler workers were back on the line Tuesday as the company reviewed the Ford deal. (Canadian Press File Photo)

The strike deadline at GM and Chrysler was extended indefinitely, and hourly employees returned to work under the old collective bargaining agreement.

Lewenza said GM and Chrysler executives wanted to further review the deal struck with Ford.

"It made a tremendous amount of sense," Lewenza said of the companies' request.

Lewenza called the extension "a good-faith gesture" but added good faith must lead to good results.

As long as progress is being made, the negotiations will continue.

"If it takes us a day or two or even three days, we will do it, but if we believe at any time, during the course of the next two or three days, that the company's procrastinating and not responding in good faith, we will give them notice that within 24 hours, we will have to withdraw our labour," Lewenza said.

However, Dino Chiodo, the CAW's chair of the Chrysler bargaining committee said the union would like to avoid a strike.

"The intent is not to withdraw our labour," Chiodo said. "The intent is to try to get a collective agreement, making sure that we're focusing on the initiatives that are important to our members, first and foremost. Right after that is to make sure that we maintain the competitiveness of the corporation."

'Damn good' Ford deal

Chrysler and GM have agreed to work within the framework of the Ford deal.

Lewenza called it "a damn good deal in these economic times."

The Ford deal includes no wage increases and no improvements in the cost-of-living adjustment until 2016. The workers instead will receive lump sum payments of $3,000 upon ratification of the deal and then $2,000 in each of the remaining three years.

New hires will make 60 per cent of full pay. The "full pay" level would be reached after 10 years, up from six years in the last collective agreement. New hires will also be enrolled in a hybrid pension plan, rather than the defined benefit plan that current workers have.

Ford also promises to create 600 new positions, mainly in Oakville. There is no new engine production slated for Windsor.

Chris Taylor is a CAW negotiator and president of the local representing Ford workers in Windsor. He's confident the employees will vote in favour of the agreement.

"Our members knew going in that we weren't going to be getting everything back from 2008-2009," Taylor said. "The expectations were modest."

Darlene Costello works on the line in Windsor. She's happy with the deal.

'I'm relieved we finally have a deal.'— Darlene Costello, Ford worker

"I’m relieved we finally have a deal. A lot of people were stressed out about it," she said. "I think it’s a good thing. We really need jobs in this area."

A Ford of Canada official says the tentative deal provides a "unique to Canada solution that will improve the competitiveness of the Canadian operations, while providing employees the opportunity to earn a good living."

The union has scheduled ratification meetings for Sept. 22 and 23. Taylor and Lewenza are confident the Ford employees will vote in favour of the tentative deal.

A labour analyst, however, said the deal between Ford and the CAW shows the weakened state of labour unions in Canada.

Charlotte Yates, a professor at McMaster University, said the CAW never would have agreed to that deal five years ago.

"This is certainly an indication … the CAW, like all unions, has been really constrained," Yates said. "They got a good deal in the context of those constraints, but it is constraint nonetheless, because they've agreed to things a few years ago the CAW, I don't think, imagined it would ever agree to."

Yates predicted GM and Chrysler will follow the pattern set by the Ford deal.

With files from The Canadian Press