The case of the YAH-64 advanced attack helicopter has fueled a new effort on Capitol Hill to slow down the revolving door through which Pentagon civilians and uniformed brass commute between the government and private defense jobs.

A $4 billion contract for production of the new helicopter has been awarded by the Army to Hughes Helicopter, though the company did not even have a plant big enough to build it. The award was made last December by Martin R. Hoffmann, outgoing secretary of the Army.

Four high-ranking Defense officials, three of whom were officially involved in the pentagon decision-making bearing on the helicopter's development, are now associated with companies linked to the $4 billion contract:

Malcolm R. Currie, former director of research and development at the Pentagon and chairman of the inhouse committee that endorsed development of the aircraft, is now an executive in a Hughes organization. He was retained by a Hughes company that Hughes officials pointed out is not engaged in the manufacture of the YAH-64.

Norman R. Augustine, who advocated the advanced helicopter project as assistant secretary of the Army and as under secretary of the Army from 1973 to 1976, recently joined Martin-Marietta Corp., which is building the firing system for the helicopter.

Lt. Gen. George Sammet, who was responsible until last month for over-seeing development of the attack helicopter as deputy commander of Army Material Development and Readiness Command, is now also an employee of Martin-Marietta.

Barry J. Shildito, an assistant secretary of defense from 1969 to 1973, is vice president of Teledyne, Inc., parent company of the firm that will build the helicopter's airframe for Hughes, Ryan Aeronautical.

In a telephone interview, former Deputy Defense Secretary William P. Clements Jr. said that when the Army told him in December that it intended to award the contract to Hughes he initially questioned whether the company was big enough to handle the job.

But, said Clements, Army executives assured him Hughes was the best choice, so he went along with their recommendation. He said Augustine and Edward A. Miller, formerly assistant Army Secretary for research and development were the Pentagon executives he relied upon most in regard to the Army attack helicopter development.

Army Secretary Hoffmann, Augustine, Sammet and Miller all conceded in telephone interviews that the helicopter case gives the appearance of conflicts of interst, but denied there was any fix. They stressed that today's procurement system makes a fix impossible unless top officials leap-frog the process by making contract awards on their own. They said this was not done on the helicoppter contract.

But the Senate Banking Committee has become so concerned about the revolving door practice in the Pentagon that it voted 15-to-0 last week to require Pentagon officials to wait at least two years before joining a firm they had dealt with in government contracts. The Civil Service Commission could decide borderline cases.

Existing laws are not as restrictive. They forbid retired Pentagon civilians and military officers from selling to their former agencies or bringing law cases against hem for a private firm.

Chairman William Proxmire (D-Wis.) of Senate Banking Committee said additional restrictions are needed to deter Pentagon officials from currying favor with firms they hoped to join after leaving the government.

Proxmire, Senate Banking Committee chairman, said Tuesday that the conflict-of-interest bill will "likely" be called up for a Senate vote late this year. If not then, he said, the vote will come early next year.

Proxmire added that the outlook is "favorable" in the House, where similar restrictions have been passed on two occasions.

The Senator said further that the new bill "certainly is in tune with President Carter's call to put an end to the revolving door" between government regulators and regulated industries.

The Council on Economic Priorities, a private research organization, recently issued a study showing that "slightly more than one fourth" of the Pentagon officials in private industry had, during their government service, done business with their subsequent civilian employers.

Hoffmann said Army evaluation boards in the YAH-64 affair had found Hughes' helicopter clearly superior to that of it's contract competitor, Bell Aerospace. Delaying the award, he said, would simply have meant payiing both contractors extra money for no justifiable reasons.

Hoffmann, no win private law practice in Washington, said the helicopter contract "does raise an appearance of conflict. I don't know how you insulate it."

To avoid any appearance of conflict in his law practice, Hoffmann said, he does not accept any business dealing with the military. "But I can pick and choose," an option that he said is not open "to a guy who has grown up in aerospace."

Not all former Pentagon lawyer-executives follow Hoffmann's off-limits policy toward representing defense contractors. For example, former Air Force Secretary Eugene M. Zuckert has been a director of Martin-Marietta since 1967, and his Washington law firm was paid $17,795 in 1976 by that contractor, according to a report filed with the securities and Exchange Commission.

Sen. Proxmire said Currie's return to Hughes - after working on military programs at the Pentagon that Hughes profits from - is "a devastating example of the pitiful weakness of present conflict-of-interest laws." (A Hughes official said Currie was on vacation and could not be reached for comment.)

Augustine said he disqualified himself last year from participating in the specific selection process for the helicopter because he had decided to return to the aerospace industry.

Augustine, who has had two hours at the Pentagon between jobs in the aerospace industry, said he will not deal with the Army in his new job of vice president for technical operations at Martin-Marietta.

"I'm not anxious to go sell soap," said Augustine in explaining why he wanted to return to the aeropsace industry after leaving the Pentagon.