A tentative sales agreement between General Motors Co. and JD Norman Industries Inc. for the Indianapolis stamping plant where more than 600 people work has touched off a power struggle within the auto workers union.

The United Auto Workers in Detroit confirmed Thursday morning that UAW Local 23 will vote Monday on Illinois-based JD Norman's proposal to buy the plant.

"There is a tentative agreement," UAW spokeswoman Michelle Martin said via e-mail. "There will be an informational meeting on Sunday and a vote on Monday."

However, local bargaining committee chairman Greg Clark said an overwhelming majority of the 631 represented workers at the plant voted on May 26 not to negotiate with JD Norman. The majority still do not want to consider the latest proposal or vote on it, he said.

Clark said he believes UAW's regional and international representatives don't have the right, under the UAW's constitution, to override that stance.

Higher-level union reps didn't communicate with him about the meeting, he said, and he took down posters at the plant advertising it.

"This is a law," Clark said. "The constitution is the supreme law of the UAW."

Clark added that he's not sure about his next step.

UAW Region 3 Director Mo Davison said Thursday morning in a prepared statement: "The International Union has in the past and will in the future, call meetings when we have vital information to share with our membership.  Our members' livelihood is hanging in the balance and they deserve to hear the facts so they can make an informed decision."

GM plans to close the massive sheet metal-stamping plant just west of downtown by Sept. 14, 2011, if it isn't sold first. To outsiders, JD Norman would appear to be a potential savior of jobs and tax revenue for the city, but many who work there don't see it that way. Like Clark, they've transferred to Indianapolis from other GM plants in hopes of staying with the company long enough to collect retirement benefits.

Clark said previously that he thinks GM will find work for him and other employees at other plants, but that's not an option if the local facility stays open, and if the union starts working for JD Norman.

There is a camp within Local 23, led by President Ray Kennedy, that wants to stay. Kennedy could not be reached for comment this morning. Clark said he believes most people on Kennedy's side already qualify for GM's retirement, but want a chance to keep working, even if for lower wages, in Indianapolis.

Officials for JD Norman, based in Addison, Ill., did not return a phone call this morning. The privately held company describes itself as a diversified manufacturer of metal components and systems with operations in the United States and Mexico. It supplies companies in the aerospace, defense, appliance, automotive, building technologies, electrical, energy and medical industries.

The company has acquired seven stamping plants since 2005—the last one being HSM Industries in Mexico in November.

UAW Local 23's current four-year labor contract with GM, negotiated in 2007, contains a two-tiered system in which new employees earn about $15 an hour compared with the prevailing $29-an-hour wage for more experienced workers.

JD Norman doesn't have to assume GM's contract with the union, but because it would be taking over the same metal-stamping work, it has to recognize and bargain with the incumbent union, said Marquita Walker, assistant professor of labor studies at IUPUI.

As for the UAW's internal dispute, Walker said it's typical of struggles throughout organized labor, especially since the recession. Local chapters are pushing for democratic union governance, but they've gotten little traction.

"The power resides where the money is," she said. "The money is in the national and international. They collect the dues. They are able to hire really nifty attorneys that know labor laws inside and out. Until the rank-and-file are able to amass the funding... it's not going to happen."

UAW spokeswoman Martin said the union would not release details of the JD Norman proposal before the vote.