WASHINGTON (AP) _ A special Navy tribunal formed to investigate allegations of illegal gift- giving by contractors to retired Adm. Hyman G. Rickover began interviewing officials of the General Dynamics Corp. on Monday, sources said.

The sources - Navy officers who agreed to discuss the matter only if not identified - said the three-man tribunal convened Monday morning and met well into the afternoon with a group of company executives to discuss the firm's relationship with Rickover.

In other developments related to General Dynamics:

-Rep. John D. Dingell, D-Mich., asked Defense Secretary Caspar W. Weinberger for information about a security clearance granted in 1974 to Lester Crown, a member of General Dynamics' board of directors, when he was the subject of a bribery investigation.

-A White House spokesman denied that presidential counselor Edwin Meese, who is awaiting confirmation to become attorney general, had been contradicted by Navy Secretary John F. Lehman Jr. in describing his involvement in a contract dispute with General Dynamics.

General Dynamics, one of the nation's biggest defense contractors, is facing a host of investigations on Capitol Hill, at the Pentagon and at the Justice Department involving Rickover as well as the circumstances surrounding a 1981 settlement with the Navy of a huge cost overrun claim.

General Dynamics builds the Navy's nuclear-powered Trident submarines, and company officials have acknowledged privately giving Rickover some gifts of jewelry. Rickover, after a career that spanned six decades, retired on Jan. 31, 1982. He has acknowledged receiving some gifts from shipbuilders, but adamantly denied ever providing favors in return.

Navy contracts routinely prohibit the dispensing of gifts or other favors to Navy officials. Last November, Dingell, the chairman of a House investigations subcommittee, demanded that General Dynamics' submarine contracts be canceled because of its gift-giving.

Lehman rejected that demand on Nov. 21, but promised to form a special tribunal to investigate the matter further. He also disclosed at the time the Navy had evidence that General Dynamics and three other contractors ''did in fact provide gifts and gratuities to Adm. Rickover.''

Dingell, whose subcommittee has been probing General Dynamics for months, asked Weinberger whether the Defense Department was aware of the bribery probe when it granted Crown a security clearance.

''We would appreciate being advised of the security clearances, including special access and intelligence, that have been granted to Lester Crown by the U.S. government,'' Dingell wrote.

''In addition, because of the subcommittee's interest in determining whether the corporation and its officers may have been derelict in their reporting requirements, we request that Lester Crown's security files be made available for review by the subcommittee staff.''

According to Dingell, a federal grand jury in 1974 named Crown as an unidicted co-conspirator in a probe of bribes paid to Illinois state legislators, several of whom were indicted and convicted.

Neither General Dynamics or the Pentagon would comment in depth on the Dingell letter.

''We just received a copy of the letter. We will withhold comment until we have a chance to review it,'' said Joe Sutherland, a spokesman in Washington for General Dynamics Corp.

A Pentagon spokesman, who spoke only on condition of anonymity, said Weinberger had not answered the letter yet and that there would be no comment until Dingell received a formal reply.

At the White House, meanwhile, a spokesman disputed suggestions that Meese had erred in telling senators recently there had been no contact between himself or his staff and the Navy when General Dynamics was pressing a cost overrun claim of $100 million.

In August 1981, Navy officials had vowed to deny General Dynamics any further submarine contracts because of the claim. The company dropped its claim several months later and negotiated new contracts after a series of meetings between company executives and administration and Pentagon officials.

Meese has said he met with General Dynamics chairman David Lewis on Aug. 7, 1981, and was told of the dispute, but concluded the White House would not become involved.

On Friday, however, Navy Secretary Lehman wrote Sen. William Proxmire, D- Wis., to say that while he could not recall discussing the matter with Meese, ''my best recollection is that a message was conveyed during that period from a member of Meese's staff to the effect that the Navy should continue to do what it was doing and that Mr. Meese did not wish to become involved in the matter.''

Bruce Chapman, a White House spokesman for Meese, said Meese has no record of any conversation between his staff and Lehman and ''there's no contradiction in any event.''

''This involves recollections going back to 1981,'' Chapman added. ''And it's hardly earth-shaking that Lehman recalls Meese didn't want to get involved.''