When Congress voted in 1979 to form a Cabinet-level Department of Education the planners decided to throw in the Defense Department's overseas dependent schools and their 9,000 employes as well.

But the Reagan administration came to town intent on dismantling education as a Cabinet agency. While that plan seems dead for this session, administration officials are well on the way to blocking the transfer of the Pentagon schools.

In early May, the Senate passed, 58 to 39, an amendment by Sen. Dan Quayle (R-Ind.) to the Defense authorization bill that would keep the DOD schools under control of the military. The $400 million-a-year system operates about 270 schools, serving 135,000 students in more than 20 foreign countries.

Quayle said that when the 5,000-employe Education Department first was being debated in Congress, the military schools' transfer came up "to give it some credibility in numbers for creating" the new agency. He claimed the transfer would disrupt the smooth operation of the schools.

Sens. Robert T. Stafford (R-Vt.), chairman of the Senate education subcommittee, and William V. Roth Jr. (R-Del.), chairman of the Governmental Affairs Committee, opposed the amendment, in part because there had been no hearings on it. "This amendment represents another attempt by the Department of Defense to end run the committee system of the Senate," Stafford said during the debate.

The bill has yet to reach the House floor, but several administration officials and congressional aides say a ban on the transfer is likely to pass.

The National Education Association, the teachers' union that lobbied hard to establish Education as a Cabinet agency, still favors the transfer. "We opposed it Quayle's amendment in the Senate and certainly will in the House," an NEA lobbyist said.

NEA's overseas affiliate won an election last month for the right to represent most of the Defense schools' 7,000 teachers.

William L. Smith, the Department of Education official who headed a team last year that studied the proposed transfer, said his report concluded that the Pentagon "is doing a marvelous job running those schools."

In a March letter to Congress asking that the transfer be blocked, Defense Department general counsel William H. Taft IV said the military provided its schools with many support services, ranging from mail delivery to physical security, that Education would find difficult to duplicate.