Except for the three blindfolded Arab prisoners riding in the back of one of the trucks, most of the men in the convoy were smiling. Their grinning faces could be seen through the windshields of about 12 vehicles that lumbered slowly down a narrow mountain road. They were headed south.

The convoys have been rolling for several days, carrying soldiers and the dismantled remnants of what was Israel's defense line along the Awwali River. The trucks in the convoy were laden with the litter of a departing army and with huge concrete blocks that the Israelis used to barricade the entrances to their bases and outposts in the hostile southern Lebanon countryside.

For the soldiers who are departing with the equipment, there is a clear sense of liberation from what has become the increasingly dangerous task of military occupation.

There is also disgust with the ways of Lebanon and deep disillusionment, especially with the Lebanese Christians, who had been thought of as Israel's allies in this country of warring religious factions.

"I was scared all the time," said one soldier, Sgt. Benny Pakulov. "It's their problem, not ours anymore. We ate it enough here already."

Another soldier, who asked not to be identified, said of the Christians: "They proved to be unreliable allies. They didn't do anything, and when they did, they did Sabra and Shatila," referring to the massacres of Palestinians at those refugee camps in west Beirut.

The soldiers were among dozens here who watched idly as a large construction crane with Hebrew lettering on its sides lifted one of several temporary housing units onto a flatbed truck in preparation for the trip back to Israel.

All along the Awwali River this week, similar scenes are unfolding as the Israeli Army prepares to execute the first stage of a planned three-stage withdrawal from southern Lebanon. Israel spent millions of dollars to establish the Awwali line in September 1983 when it withdrew from the Chouf Mountains south of Beirut.

Now it is spending millions more to dismantle the line. The Army bases are clogged this week with heavy construction equipment -- cranes to lift the housing units, trucks to haul the refuse, bulldozers to demolish the protective earthen embankments the soldiers built -- that belong to private Israeli contractors.

The first stage of the pullback is scheduled to be completed by Feb. 18. Before then, most of the bases and outposts along the line, this one included, will be dismantled. On Feb. 18, the last of the soldiers will leave, pulling away from the Awwali River Bridge on the Coastal Highway, away from Sidon, the largest city in southern Lebanon, away from the Palestinian refugee camps east of Sidon.

Along the coast, the Israelis will move as far south as the Litani River. From that point, the new line will run sharply northeast, keeping within the Israeli zone of control the city of Nabatiye, a center of Moslem Shiite resistance, and the Christian town of Jezzin.

According to Israeli Army figures, the area to be evacuated in the first stage represents 5 percent of Lebanon and slightly less than 20 percent of the territory now under Israeli occupation. It is the most densely populated section in the Israeli zone, containing as many as 400,000 Lebanese and Palestinian civilians. In withdrawing from this area first, the Israelis will almost cut in half the population under their control.

There will not be, however, a parallel reduction in the size of the Israeli presence in southern Lebanon. Estimates of the number of Israeli soldiers in Lebanon range from 12,000 to 20,000, and the bulk of them are concentrated in eastern Lebanon near Syrian Army lines. The pullback in the east is stage two of the withdrawal plan, but the time for the second step has not been set and will be affected by how well the withdrawal along the coast goes.

The Israeli Army now regularly brings journalists and photographers here to Mashnaka, a command post and ordnance base situated high on a flat bluff betwen Jezzin and Sidon, to see the Awwali line being taken down and talk to some of the base's several hundred soldiers.

The Army chose as the main spokesman for the Mashnaka unit a 26-year-old soldier with close-cropped hair who identified himself as "Captain Teddy." He was chosen apparently because as a youth he lived for eight years in Chapel Hill, N.C., where his father was studying economics, and speaks flawless English with the softly melodic accent of North Carolina.

He sat on the hood of a jeep, his rifle slung over his shoulder, and proudly called himself "a combat soldier." This was his answer to a question about how much it was costing to dismantle the Mashnaka base. Captain Teddy said he knew nothing about things like costs, nor did he seem to care.

"The important thing is we are not leaving with our tails between our legs but with our heads held high," he said. "We are leaving only because of the government's decision to withdraw. Militarily, we could stay here as long as we like."

For his part, Captain Teddy said he has seen enough of Lebanon. "It's a beautiful country physically, but the problem is you have to keep your eyes on other things and not the view," he said.

He said he hoped the Israeli withdrawal would not be followed, as is widely feared, by an outbreak of fighting among the various Lebanese factions. But after 2 1/2 years here, the Israelis have learned not to count on the Lebanese or, to judge by Captain Teddy's comments, to care much about them.

"This isn't a country," he said. "This is a collection of sects and religions, each armed to the teeth and each interested in killing each other."

This was true of the Christians as well as the Shiite and Sunni Moslems and the Druze. It was the Christians who disappointed the Israelis in the early fighting in 1982, and who proved to be at least as ruthless as any of the other sects in Lebanon's bloody communal violence.

"Maybe some of them are bitter about the withdrawal," Captain Teddy said of the Christians in the villages along the road that runs from Jezzin to the eastern outskirts of Sidon. "But that's their problem. They can stand on their own two feet. They have to solve their own problems."

Many of those Christian villagers will lose the protection of the Israeli Army in the first stage of the pullback. How many is not clear because it has not been determined exactly where the new line will cut across the Jezzin-Sidon road, leaving some villages outside the Israeli zone and Jezzin and nearby villages still within it. The new line in any case will be "flexible," an officer said, meaning the Israelis reserve the right to reenter periodically the area they are about to leave.

A western observer of Lebanon's often vicious form of local politics said concern about the Palestinian refugees in the area to be evacuated may be misplaced. When the Israelis leave, he said, "it is the Christians who will be the endangered species."

Christians in the area expressed mixed sentiments about the impending withdrawal. Several of them had gathered on the open, second-floor patio of a home that overlooks an Israeli checkpoint at the Bisri crossing point of the Awwali River. As they watched, Josslin Helou and Mona Boulos, both 20, said they were not afraid of the Druze militias that control the Chouf Mountains just across the river.

"We are strong," said Boulos, who lives in Jezzin and will remain behind Israeli lines until the second stage of the withdrawal is completed. She added, in defiance of her country's history, "We are all Lebanese, and we will live together in Lebanon."

But in a restaurant in Jezzin, Ramzi Khammar said the Christians where he lives "are scared to death." Khammar is a Baptist minister who lives near Sidon in the Christian village of Miyumiye, located next to a Palestinian refugee camp of the same name. In 1982, the villagers attacked and burned the camp, another chapter in the Christian-Palestinian warfare that has raged for years in Lebanon.

In Miyumiye, Khammar said, the people are stockpiling canned food, bread and wood and are in a much higher state of alert than they were before the Israeli withdrawal. Meanwhile, Palestinian women and children are moving from the refugee camp to the larger and better protected Ain Helweh refugee camp, he said.

"There are several rats, but no one big lion to control the situation" after the Israelis leave, Khammar said.

As they prepare to leave Mashnaka and other outposts along the Awwali, Israeli soldiers appear to recognize that for more than two years they have been the "big lion" here, bringing a measure of enforced order to the area. That role has made them a target, and they will leave the steep, green hillsides along the Awwali gleefully. Some of them will also leave with a gnawing sense of disappointment and failure.

"I feel good that we're going," said Sgt. Yossi Elbaz. "But I don't feel proud about leaving the Christians behind. I wouldn't want to be in their shoes, but we can't think about that anymore."