The administration's top Latin American expert, in a meeting with Chilean President Augusto Pinochet, did not press for an easing of repression in that country and received only vague assurances about an eventual transition to democracy, a senior State Department official said yesterday.

The official, who under the ground rules could not be identified, briefed reporters following the trip to Chile by Langhorne A. (Tony) Motley, assistant secretary of state for inter-American affairs.

Motley's trip reflected the Reagan administration's growing concern over the Chilean military regime's recent crackdown on dissent. Pinochet renewed a state of siege in November, imposing strict censorship, closing six opposition newspapers and arresting thousands of people.

The State Department official said Motley believed that it would be counterproductive to urge Pinochet to take specific steps to assure that democracy is restored by 1989, as the government has promised. Pinochet reportedly was in no mood to be told what to do.

During the meeting, the official said, Pinochet "did not give . . . any specific dates nor calendars nor chronology" about democratic reforms. But Pinochet "assured" Motley that these steps "would be carried out," the official said. Motley did not believe it was "appropriate" for an American "gringo" to try to "muscle" Pinochet on a visit to Santiago, the official said. He said there is "a heck of a lot to be done" in restoring human rights in Chile, but that "the elements are there" for eventual progress.

The administration believes it has few tools with which to influence the Pinochet regime since U.S. military aid ended in 1981.

Administration officials have said recently that they have abandoned "quiet diplomacy," their preferred method of dealing with human-rights violations by U.S. allies, because it has failed in Chile. At the same time, Motley's visit indicates that the administration also is reluctant to apply direct pressure. The United States made its first concrete show of displeasure by abstaining on a vote to provide Chile with a $130 million loan from the Inter-America Development Bank.

President Reagan lifted a Carter administration boycott on U.S. support of international loans for Chile in 1981. Fifty-five House members are sponsoring legislation to resume the boycott.

Motley believes that quiet diplomacy must remain part of the U.S. approach, although American officials should feel free to "express disappointment or outrage" about Chilean actions, the official said.

"We're not going to conduct single-issue politics," he said. "That may have been a mistake of the Carter administration," which placed heavy emphasis on human-rights policy.

The official said a sixfold increase in terrorist incidents last year, much of it by radical forces in Chile, is part of the reason that earlier human rights progress "seems to have slowed down and stopped."

"It takes two to tango," the official said, adding that Pinochet's opponents have failed to agree on a common strategy.

Opposition leaders are of two minds about U.S. intervention, the official said. Some of them told Motley that "it would be helpful for us if you would beat up on Pinochet," but quickly added that "we don't want the U.S. to interfere in the internal affairs of Chile."