April 2, 1983

The National Highway Traffic Safety Administration said today that it had reached a preliminary finding that could lead to a recall of more than five million General Motors vehicles. The apparent defect involves the split rear axles of the mid-size A-body line of cars manufactured in model years 1978 through 1980, and could cause the wheels to separate from the axles without warning. This could produce a potential ''catastrophic event'' if the failure occurred while a vehicle was in motion, the safety agency said.

In the midst of the jungle six miles from here, a barbed-wire barrier marks the frontier between Costa Rica and Nicaragua. A concrete marker, knee-high and nearly covered by grass, notifies the visitor that this is the border. Otherwise, the barrier looks more like the work of a farmer trying to keep his cattle from wandering too far. In recent weeks, as in the past, this border has become a problem for Nicaragua. Refugees fleeing Nicaragua have been crossing it in greater numbers - over 800 in the last three weeks. At the same time, Costa Rican border patrols have found small abandoned base camps on Costa Rican territory that were said to have been organized by anti-Sandinist Nicaraguans.

President Reagan's special commission studying ways to deploy the proposed MX missile has decided to recommend basing 100 missiles in existing but newly strengthened silos, Administration officials said tonight. Whether Congress, which has already voted against deploying the MX in the present Minuteman missile silos, will agree to the recommendation is a ''tough call,'' one official said. Perhaps no military decision in recent times has been so troubled as finding a base for the MX missiles. The critical issue has been to find a base in which the missiles could survive a nuclear attack and be fired in retaliation.

The Reagan Administration has held up final approval of the sale of 75 F-16 fighter-bombers to Israel not because of any specific Israeli violation of arms agreements with the United States, but because providing the planes now would violate ''the spirit of the law,'' Administration officials said today. They added that the approval was also being delayed to prod the Israelis to reach agreement on withdrawal of their forces from Lebanon and to avoid angering friendly Arab governments. President Reagan said Thursday that approval of the shipment of the F-16's was ''forbidden by law'' because of Israel's ''occupying'' of Lebanon. Israeli officials, including Foreign Minister Yitzhak Shamir, reacted angrily today to Mr. Reagan's statement.

In an unusually strong protectionist action, President Reagan today ordered a tenfold increase in tariffs for imported heavyweight motorycles. The impact of Mr. Reagan's action, which followed the unanimous recommendation of his trade advisers, is effectively limited to Japanese manufacturers, which dominate every sector of the American motorycycle market. The action was exceptional for protecting a single American company, the Harley-Davidson Motor Company of Milwaukee, the sole surviving American maker of motorcycles. The only comparable trade action by this Administration, the President's decision last May to impose quotas on sugar imports for the first time since 1974, was aimed at an entire industry.