Skilled trade workers, which account for 5,000 of Chrysler's 26,000 UAW rank and file employees, voted no on the contract proposal, while production workers voted yes.
Union leaders at the local level have agreed to vote on whether or not to ratify the contract, anyway, which could alienate skilled workers who turned it down.
UAW President Bob King said this month that, "for items that are specifically related to skilled trades, skilled trades has to pass those items."
But a source told the Free Press that Chrysler would be unwilling to renegotiate any part of the contract, which would automatically send it into arbitration.
Former General Motors labor negotiator Art Schwartz said a split in the voting was extremely rare. "I don't remember this ever happening," he said.
"It has happened with local contracts but it's never happened in my memory in a national agreement," he said.
Chrysler is trying to pare down the number of skilled trade categories to keep it competitive with foreign companies using non-union labor in U.S. factories. The contract proposal skilled trade workers rejected eliminates 27 worker categories, such as brick mason, carpenter and cement finisher, the Free Press said.
"All of the domestic companies have been moving to fewer skilled trades workers, fewer classifications and more flexibility. But they still haven't caught up to the transplants," Schwartz said.