DETROIT, Oct. 15  United Automobile Workers leaders approved a new tentative agreement with Chrysler LLC today, clearing the way for a vote by about 45,000 Chrysler workers. But the leaders of several union locals voted against the contract, which could spell difficulties for its ratification.

Several union leaders said they were concerned that the contract did not include specific promises by Chrysler for future work at their plants, beyond the vehicles they build now.

The meeting of the U.A.W.’s Chrysler Council was held at Cobo Center in Detroit. The U.A.W. reached a tentative agreement with Chrysler last Wednesday after a six-hour strike.

The contract is similar to a new agreement between the U.A.W. and General Motors.

Local leaders leaving today’s meeting said that the contract had been approved by the council, but that the vote had not been unanimous, unlike a similar vote by leaders of G.M.’s local unions.