Negotiators for the U.A.W. and G.M., the nation’s biggest automaker, reconvened for meetings after failing to reach a deal before their contract expired late Wednesday.

The union has agreed to a day-by-day extension at G.M. to complete the outstanding issues separating the two sides, including job commitments in plants, signing bonuses for workers and a pay increase for entry-level employees. Talks will resume 9 a.m. on Friday.

The union’s president, Bob King, has been conducting parallel talks with G.M. and Chrysler, the two Detroit automakers that were bailed out by the Obama administration in 2009.

But Chrysler abruptly asked for a weeklong contract extension on Wednesday night after Mr. King did not attend a scheduled session with Chrysler’s chief executive, Sergio Marchionne.

Instead, Mr. King seeks to set a pattern on wages and bonuses at G.M., and then try to match it at Chrysler and Ford Motor.

“It looks like the pattern, at least initially, is going to be set at G.M. rather than Chrysler,” said Arthur R. Schwartz, president of the consulting firm Labor and Economic Associates in Ann Arbor, Mich.

The union cannot strike either G.M. or Chrysler as a condition of their federal aid packages. That is not the case with Ford, which turned itself around without government assistance.

It is not unusual for the union to grant a contract extension if it is close to a deal with one automaker. G.M. has been determined to be the first company to settle and establish a cost structure that will help its comeback.

Mr. King, however, may find the going rougher at Chrysler, which is owned by the Italian carmaker Fiat and has yet to turn as profitable as G.M. or Ford. Mr. Marchionne was clearly peeved with Mr. King for not honoring an agreement to negotiate face to face on the last day before the current four-year deal expired.

The Chrysler chief executive sent a scathing letter by fax to Mr. King, noting that he had flown in from Europe to finish the negotiations. “You, unfortunately, could not be here, I am told, due to competing engagements,” Mr. Marchionne wrote. Mr. King received the fax in the middle of his discussions with G.M.

Mr. Marchionne then said he would be unavailable to meet with Mr. King again until next week. Mr. Marchionne also, for the first time, brought up the possibility of the contract being arbitrated if an agreement could not be reached.

“If that happens, nobody knows what we’re getting into,” Mr. Schwartz said.

Nick Bunkley contributed reporting.

Article source: http://feeds.nytimes.com/click.phdo?i=02d123258db051cd5eeda29c13c155dc