Nine months after Gen. Efrain Rios Montt seized power here through a military coup, his government has "pacified" major portions of northern and western Guatemala that had been dominated by Marxist-led guerrillas.

After months of deaths and massive dislocation--sometimes at the hands of the rebels, often at the hands of the Army--Indian peasants gradually are resettling many villages now tightly regimented and controlled by the government. Roads are open, and commerce is reviving.

In such areas the death toll has dropped dramatically, according to peasants, priests, soldiers and civil officials interviewed in the war-torn provinces of Quiche, Huehuetenango, Solola and Chimaltenango over the last 10 days.

The success of the government's initially savage but sophisticated campaign against the rebels has come without significant U.S. military assistance, and top field commanders say that none is necessary now to finish the guerrillas.

"We do not need any military aid," Col. Roberto Enrique Mata, commander of Quiche Province, said.

Commenting on reports that the Reagan administration intends to approve the sale of helicopter parts to this government despite strong opposition by human rights groups, Mata said, "It is useful to have air transport," but "it is not indispensable."

In fact, U.S. manufacturers have provided some essential pieces of equipment used by the Guatemalan Army under commercial arrangements that sidestep human rights restrictions on military sales.

Among the U.S. equipment are Bell 412, 212 and "Long Ranger" helicopters. The military provided a Bell 412 for myself and other reporters to visit some of the towns mentioned in this story. The Air Force pilots in the helicopter had what appeared to be brand new, U.S.-manufactured armored seats. Most of Guatemala's new weapons, including standard issue Galil assault rifles, are Israeli.

The government's initial victories were achieved at a cost in noncombatants' lives that U.S. politicians could never have condoned publicly, and the present stage of the war is based on rigid control of the rural population and extensive civil action programs for which Washington's military technology is largely irrelevant.

Army and other government officials now emphasize their efforts to meet the economic and social needs of the long-neglected people they say they have "rescued" from the guerrillas. What Rios Montt calls his strategy of "beans and rifles" is more reliant on beans every day.

Some senior government officials claim that there was a dramatic change in the conduct of the war from March 23, the day that Rios Montt took over.

Urban death squad activity, which Amnesty International charged was directly controlled by Rios Montt's predecessor, president Romeo Lucas Garcia, ended almost as soon as he was ousted.

In the countryside, however, the systematic scorched-earth counterinsurgency campaign begun in November 1981 by the ex-president's brother, then-Army chief of staff Benedicto Lucas Garcia, continued and intensified through the summer.

As the pressure mounted, the civilian population, which had given at least tacit support to the rebel armies, discovered the guerrillas could not protect them from the relentless military sweeps in successive areas of the countryside, forcing out the population as well as the guerrillas.

The rebels also appear to have resorted to increasingly brutal intimidation as they saw their base of support eroded by fear, death and disillusionment.

The peasants, left with no middle ground, began opting for the side that appeared to have superior force.

Francisco Xeto, 40, came down from the mountains to a government refugee camp at Nebaj, Quiche, at the end of August. Last year, he said, the 250 families in his settlement above the town had been left in relative peace. "The soldiers didn't do anything to the people," he said.

Other villagers say they were in almost constant contact with guerrilla soldiers.

Now, Xeto said, "We cannot live there. If we go with the soldiers the 'subversives' kill us. If we go with the subversives the soldiers kill us, and we have no life that way."

The hardest months for Xeto, he said, were April, May, June and July, when he and his family were forced to flee and take refuge deep in the mountains.

"There was nothing to eat," he said. "They burned our houses."

When asked who did it, he responded, "Soldiers." What soldiers, he was asked. "Soldiers of the government."

"Many families died," said Xeto, at the hands of "the same soldiers."

He estimated 30 of his neighbors were killed by the government "apart from those who disappeared."

"The guerrillas told us, 'Don't worry, when the soldiers come we'll protect you,' " Xeto recalled.

"But when they came, there was nothing," he said.

Xeto finally turned himself in to the Army with his family, he said, "so as not to die, for my children, the little ones, because you cannot watch your children die fleeing."

He had heard that the Army would not kill him if he came down with his family, and that turned out to be true. Now he says that although soldiers are everywhere in the camp, "we are at peace; we are left alone." He said he believes that the other 200 families still in the mountains would come down if the guerrillas let them.

When the government reestablishes control of a village, it sets up a civil administrative structure. In towns like Nenton, near the Mexican border, government employes who had fled were ordered to move back to the deserted town with the troops if they wanted to continue drawing salaries.

All able-bodied men in government-controlled villages are organized into civil patrols. In some areas, such as Pujujil, Solola, able-bodied men are as young as 8 years old.

The specific commitments of the patrols vary from village to village, but basically each member must work a 24-hour shift three or four times a month walking the countryside and guarding the village.

Once the system is established it tends to become self-enforcing. If a man refuses to participate in the Huehuetenango town of San Mateo Ixtatan, according to patrol chief Juan Mendez Gaspar, 62, "We ask why? Could it be he is connected with those up in the mountains?" Mendez Gaspar said, however, that no one to date has refused to serve.

He said that everyone who had been connected with the rebels in the town is now dead. Asked who killed them, he said that they might have been murdered by "the subversives" themselves.

The civil patrols are in many cases armed with nothing more than sticks and machetes. At best there is usually only one old M1 rifle for every five or six men on patrol.

The guerrillas have attacked the patrols with a vengeance, and the patrols have retaliated when and where they could, sometimes with the zeal of converts.

Mata and other officers in Quiche estimate that most of the patrulleros were once guerrilla supporters or militiamen.

The village of San Bartolome Jocotenango was one of the first organized in civil patrols as a pet project by Benedicto Lucas in December 1981. After the first patrol chief was killed by the guerrillas only two weeks after taking the post, according to Mayor Diego Lux, the people who had already been organized "rose up" and killed 100 people the mayor called "subversives," who were the residents of two of the village's outlying settlements.

Col. Gustavo Adolfo Mendez, commander of Huehuetenango, says that there are 60,685 men organized into defense patrols in his province alone.

Mendez was asked about an incident marked on his combat map, which showed a clash between "subversives" and a civil patrol near the Mexican border on Dec. 26. One subversive was captured, the notation said.

Asked what happened to the subversive, Mendez said, "the men in the patrol get very mad." Mendez smiled. The subversive was "captured dead," he said.

"After seven months of fighting from Chimaltenango to Quiche, we knew that all the population was subversive," Mendez said.

Under what he called "the new norms" of the government, once "security" is established, "development" is viewed as the best way to attract and hold the people. The Army in Huehuetenango is paying 10,400 peasant men in food supplies to build roads with shovels, picks and wheelbarrows and to work on about 100 "infrastructure" projects.

In Huehuetenango and the other troubled provinces schools and health centers are being reopened.

The guerrillas who once controlled much of Huehuetenango now do little more than blow up power lines.

For the moment, as one priest put it, the Army and government are working hard to be "nice guys" wherever they think they have established complete control. "But the big fear," the priest said, "is what will happen if the guerrillas make a next move. Then will the Army go back to step one? The massacres? Nobody knows."