– Personalities and experience are likely to play major roles in contract talks between the United Automobile Workers union and Detroit-based automakers.

Sergio Marchionne, head of Fiat Chrysler Automobiles, could again be the wild card. He has shown himself in the past to be a hands-on CEO who's not afraid to take drastic steps or interrupt the flow of talks if he doesn't like how they are proceeding.

Marchionne's strong personality and global merger aspirations cast a long shadow on the FCA bargaining table where there are newcomers in both key roles. Norwood Jewell heads the union team for the first time, and Glenn Shagena is the company's newly appointed head of employee relations with the abrupt departure June 9 of longtime company bargainer Al Iacobelli.

At the other end of the spectrum is Ford with the seasoned Mark Fields as CEO, a man who ran operations in the Americas before his ascension to the C-suite. The corporate team is filled with top executives who have led talks in the past, including Joe Hinrichs, who now leads the Americas; John Fleming, who has overseen labor affairs since 2009, and chief negotiator Bill Dirksen.

The union side is led by senior statesman Jimmy Settles, in his third term leading Ford's UAW division. He believes the UAW should negotiate its contract with Ford first. "Experience matters, and I got the most," he said of his 12 years.

Somewhere in the middle is General Motors under the new leadership of CEO Mary Barra. At the table: a UAW rising star in Cindy Estrada across the table from Cathy Clegg, who takes over the top job after Rex Blackwell, the recently appointed vice president of labor relations, unexpectedly retired on June 1.

Clegg led GM's contract talks in 2011 and will add the 2015 talks to her duties as head of North American manufacturing and labor relations. "Her close work with Blackwell and the UAW over the past few years enables a seamless transition," GM spokeswoman Katie McBride said in a statement.

Orchestrating it all: Dennis Williams, who is the new UAW president, but isn't new to bargaining.

"I've been in hundreds, if not thousands, of negotiations in my life," Williams recently told reporters, expressing faith in the ability of the teams assembled to hash out contracts affecting about 140,000 unionized workers.

He said he is not fazed by the recent changes on the company side.

"They're professionals. They are very good at what they do," Williams said. "They wouldn't be there if they weren't. There are too many people out there who are very bright."

Companies often make changes at the top, and the timing is not always ideal, Williams said. "But what I have found is sometimes new faces and new thoughts actually help."