The Army will try to put its antiballistic missle on the comeback trail this month.

This time, instead of trying to protect whole cities or missile sites with such past defense systems as Sentinel or Safeguard, Army leaders will describe how the ABM could protect a single MX missile hidden in a garage.

The MX is the new blockbuster intercontinental ballistic missile President Carter has decided to build for the 1980s and 1990s. Pentagon leaders fear the Soviets will soon be able to destroy the current force of ICBMs fixed in silos in the West.

The first MX missiles are expected to be deployed around 1986.

Each MX, in contrast to the 1,000 Minuteman and 54 Titan ICBMs already deployed, would be hauled from one concrete garage to another. The garages would be spread around racetracks built on valley floors in Nevada and Utah.

The idea is to keep each of 200 MX missiles moving among 23 identical garages in such a way that Soviet gunners would never know which garage held a missile.

However, the possibility arises that the Soviet Union would end up building enough nuclear warheads to cover every garage, whether it held a missile or not.

In that case, Army leaders are telling Air Force counterparts in secret briefings, it would be good to have an AMB to protect every garage that held an MX missile. Paper studies suggest such an ABM defense is possible, according to Army leaders at the Ballistic Missile Defense center at Huntsville, Ala.

This proposed MX protector already has a name -- LOAD, for low altitude defense. A LOAD missile would be programmed to explode in the "window" in the sky that the enemy warhead would have to fly through to hit the MX garage.

The LOAD warhead, according to those working on the project, could be nuclear or nonnuclear. Either would be enough to destroy the incoming warhead or push it off target.

Air Force leaders running the MX program have discussd LOAD with Army missile officers at Huntsville. They stress that the new ABM would be "a safety valve" for the Mx. LOAD would not be deployed if the current ABM treaty with the Soviet Union remains in force. However, these officials reason, the Pentagon must at least consider an ABM for the MX. Army leaders will make that case in a series of closed meetings this month and next.

One such meeting will be with Seymour L. Zeiberg, deputy undersecretary of defense for strategic and space systems. Plans calls for him to be briefed at the Army's Ballistic Missile Defense Center at Huntsville.

The Army is preparing another ABM briefing for military and civilian leaders of the Air Force, apparently in hopes of getting their blessing for ABM money in the Pentagon budget now in preparation.

LOAD may stay on paper after civilian leaders at the Pentagon hear the Army out. The Army spent $6 billion on earlier ABM deployment schemes before phasing down to its present paper research stage.