DETROIT — It was all smiles and optimism Monday as the United Auto Workers union opened contract talks in an official handshake ceremony with General Motors Co.

But the glad-handing may not last long with both sides a long way apart on a number of financial issues.

GM and Ford Motor want to cut labor costs that are $8 to $9 per hour higher than U.S. plants owned by Honda Motor and Toyota Motor, while Fiat Chrysler Automobiles wants to keep its costs stable. For those hired after 2007 (the Tier 2 workers), the 2011 contract lifted their hourly pay from $15.78 to $19.28. Those hired before 2007 are still making $28.50, if they work on the line, and about $33 if they are in skilled trades such as electricians, pipe fitters or carpenters.

In the new contract, the union also wants pay raises for longtime workers, an end to lower pay for entry-level workers and new product guarantees that would create jobs at U.S. factories.

Despite the differences, union officials and GM executives said they were confident at a Monday ceremony that they could negotiate a deal that will make both sides happy.

“A successful GM is good for shareholders, but it’s also good for employees,” CEO Mary Barra said.

But UAW President Dennis Williams said, “These negotiations will not be easy. But they are no more difficult than those we’ve had in the past.

“We have a membership that has, because of the economy, had stagnant wages, and we plan to address that. We all plan to bridge that gap.”

The union agreed to the lower-tier wages to help the companies as they were headed into financial problems in 2007. Hourly pay rates have been essentially frozen since 2005.

In the past, the UAW and Detroit Three have made progress in recent contract talks to lower the automaker’s overall labor costs from $78 per hour to $54 per hour for wages and benefits, according to the Center for Automotive Research. Fiat Chrysler is now equal to the German and Asian automakers’ U.S. plants ($47 an hour including wages and benefits), while GM and Ford are slightly higher.

Mr. Williams also cited job security as an issue for the talks. Companies have talked about moving production to Mexico, especially in lower-margin small cars. Last week, Ford said it would stop making the compact Focus and C-Max hybrid at a factory in the Detroit suburb of Wayne, Mich.

Presumably the production would be moved to Mexico with the plant getting a different product. Also, earlier this year, GM announced it would start building the Chevrolet Cruze compact in Mexico in addition to a factory in Lordstown, Ohio, east of Cleveland.

The union’s contracts with GM, Ford and Fiat Chrysler expire Sept. 14. Talks with Fiat Chrysler open today and Ford’s talks officially begin July 23.

First Published July 14, 2015, 4:00 a.m.