International Harvester Co. has suspended trade negotiations with the Soviet Union and is asking other American corporations to send protests to the Kremlin in a campaign to secure the freedom of a Harvester employe facing trial on currency violation charges.

At least two other U.S. multinational corporations trading with the Soviet Union have already responded to a confidential Harvester appeal and have sent protest messages to the Soviet government. About 20 other American firms and the International Chamber of Commerce have reportedly received requests for support from the Chicago-based equipment manufacturing company.

Harvester is not asking any other company to follow it in suspending business activity with the Soviets as a way of obtaining the freedom of F. Jay Crawford, who was arrested June 17 and held for 15 days before being released in the custody of U.S. Ambassador Malcolm Toon to await trial.

But the campaign to build a front of protest by American companies marks an embryonic, potentially significant shift.

Until now, the American business community has determinedly sought to keep Soviet trade completely insulated from swings in America-Soviet political relations. Harvester's move is certain to be debated intensely by business groups that have large interests in Soviet-U.S. trade.

That debate will be carried out in part in private meetings of businessmen now being called to discuss not only the Crawford case, but also President Carter's decision last week to cancel the sale of a high technology computer to the Russians and other actions that have drawn trade into the political debate over detente. Both the White House and the Kremlin are receiving blame from business groups for this unwelcome development.

The political overtones to the International Harvester appeal were evidenced at a meeting Monday at the State Department between Harvester chairman Brooke McCormick and Deputy Secretary of State Warren Christopher. Christopher indicated support for the Harvester approach to other companies, according to one account of the meeting, and promised to telephone some of the companies.

A spokesman for McCormick confirmed the meeting with Christopher and the appeal to other companies for support on the Crawford case, but declined to go into detail. He also declined to discuss the potential contracts that the company is refusing to discuss further with the Soviets until Crawford is freed. The company sold $32 million worth of earth-moving and construction equipment to the Soviet Union last year.

The Soviets released Crawford, the number two representative in Harvester's two-person Moscow office, only when the United States agreed to release two accused Russian spies, now in the custody of Soviet Ambassador Anatoly F. Dobrynin. Reports of American efforts to arrange a trade of the two Soviets for imprisoned Soviet dissident Anatoly Scharansky have raised hope among some businessmen that Crawford's release can be negotiated as part of that deal.

"For the first time the Russians have transgressed the understanding we sought to achieve with them," said a senior executive of another major corporation which has sent a protest to the Kremlin. "They made International Harvester the target for a purely political reprisal for the jailing of the two Russians here," he said.

"That is a serious problem for all of us. And it comes at a time when many of us don't see the business opportunities we expected by now. Many companies are mulling over the whole value of their Moscow operations, I think."

After the 1972 detente agreements between Soviet leader Leonid I. Brezhnev and President Nixon, 24 American companies opened up representational offices in Moscow. But nonagricultural U.S. exports to the Soviet Union have slumped to about half their 1976 level this year, and are projected by the Commerce Department to wind up at about $400 million.

One transaction accounts for more than one-third of that total - a $144 million contract negotiated by Dresser Industries of Dallas to sell the Soviets a modern plant to make sophisticated bits for oil well drills. President Carter assumed the authority to cancel a key part of the pacakage last week by placing oil technology exports on the commodities control list for export licenses.

That decision is certain to come under criticism at a gathering of businessmen in Washington next week under the auspices of the American Committee on East-West Accord, a group of about 150 businessmen and intellectuals who favor enlarged cooperation with the Soviet Union. Coca Cola, Pepsi Cola and Control Data Corp. are among the companies represented on the committee.

"We will be discussing what we can do in light of the Crawford case and the president's deicisions. Our members are concerned over these first steps by the president to use trade as an instrument to achieve internal change in the Soviet Union," said Carl Marcy, codirector of the committee.

Those moves already have been criticized by Harold B. Scott, the president of the U.S.-U.S.S.R. Trade and Economic Council, which links 260 American companies and 113 Russian trade organizations.

Placing controls on "nonstrategic" American exports "would mean substantial losses in jobs," Scott argued in a public statement. "The Europeans and the Japanese will be the gainers in any such move. The losers will be American labor . . . and the American taxpayers."

But the twin concerns of American business right now were underscored by the fact that Scott earlier this month privately visited Dobrynin to warn in muted comments that incidents like the Crawford case could alienate the U.S. business community, an extremely influential, if discreet, constituency backing detente.

The new perils to trade and detente will also be the central topic of a special policy meeting of the National Foreign Trade Council, which is being convened in mid-August in New York City. The council, an association of over 500 of the largest American companies involved in international trade, is inviting a representative of International Harvester to brief its members on the Crawford case.