CAW national secretary-treasurer Peter Kennedy says one of the companies, which the union won't name, is reviewing the plan following discussions Saturday morning in Toronto.
The proposal would see new employees earn less when they are hired and take longer to reach the top end of the wage scale.
Kennedy says the offer is key since once the wage issue is settled then the rest of the deal should be easy to nail down.
He says the union expects negotiations with the two other companies to move more quickly once one of the trio signs off on an agreement with the CAW.
The CAW has threatened job action if there is no deal by midnight on Monday, but has indicated it might hold off if progress is being made.
Ford, Chrysler and General Motors were not immediately available for comment.
Kennedy said the wage proposal is "the key that unlocks the door — once we get that confirmed with one of the three then we can go to town on all of the other issues."
"There's still a lot of big issues but that's been kind of the major hurdle we've had to get our arms around," he said, adding the union disagrees with proposals by the automakers that their Canadian employees accept a permanent "two-tier" wage structure adopted in their U.S. plants.
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