The election today of Chon Do Hwan brings to power a South Korean government less responsive to American influence and pressure than any of its predecessors, in the view of knowledgeable observers here.

Foreign diplomats and South Korean officials sympathetic to Chon point out that he has shrugged off several attempts at American pressure since he began his rise to power eight months ago. They believe he will continue to do so.

They agree that the Carter administration has little leverage with the interim government on either of the two major issues on which the State Department has recently expressed concern. These are the trial and sentencing of opposition leader Kim Dae Jung and the course of political change leading to a new constitution and elections.

The former general, as expected, was elected president unanimously and without opposition this morning by the National Conference for Unification, an electoral body created by his predecessor, the late Park Chung Hee. Of the 2,525 votes cast, all were for Chon except one, which was ruled invalid.He is expected to govern as an interim president until new elections are held sometime late this year or early in 1981, when he is considered likely to seek a regular term.

The United States has exerted broad influence in South Korea since the Korean War ended in 1953, based on its guarantee to support the country in the case of invasion and on economic assistance that largely supported South Korea in the days before economic progress made it more self-sufficient.

The U.S. still bases nearly 40,000 troops in South Korea and is committed to using them against aggression from North Korea. In the past, the troop presence has been an unofficial source of leverage for the U.S. in deealing with the South Korean government. Many believe that president Park, before his assassination in October, toned down political repression occasionally out of fear that it might trigger anti-korean sentiment in the United States and result in a troop withdrawal.

That unstated pressure has been considerably lessened by President Carter's decision not to follow through on his campaign promise of a troop withdrawal. That was underscored recently when Carter told the Boston Globe that he feels a troop withdrawal "might destabilize that whole region of Asia and have deleterious effects for us . . ."

One government official who reflects Chon's views said this week that U.S. troops here are recognized as not merely representing American "altruism," but as protecting American interests. The new leadership, he said bluntly, would resist U.S. attempts to use the military presence as a device for intervening in South Korean affairs.

"Using the troops to tell us what to do would not be a proper thing to do," he said. The government will handle domestic affairs, including the cases of anti-Chon dissidents, "in our own way," he said, adding that Americans "should leave the troops here and not comment on our domestic ways."

Foreign diplomats have noted a generation gap between Chon's group and the previous military leadership that was closest to Park, although only a few years separated them in age.

The older generals, such as Park, rose to prominence after fighting North Korea in positions subservient to American military leaders, and were more apt to accept American dominance. Chon and many of his colleagues, particularly the younger colonels around him, were among the first classes to graduate from South Korea's own military academy, and are more apt to rely on their own professionalism.

Chon first showed his disdain for American leadership during the military coup on Dec. 12, when he ordered South Korean troops moved to support him in Seoul in defiance of rules governing the joint command of forces here. On occasions since, he has brushed aside American efforts to restrict the military's growing power, culminating in a military crackdown on May 17.

U.S. officials recently have warned the government of their concern about the conduct and outcome of the trial of Kim Dae Jung, who was arrested and charged with plotting sedition following the May crackdown on dissidents. Chon's reply, if any, has not been made public, although it is understood that there has been no assurance given that Kim will not receive the death penalty.

If the military tribunal orders the dath penalty, Chon would be in a position to spare his life by commuting the sentence to life imprisonment, and there has been speculation that Kim's fate is a matter the government may try to use as leverage in dealing with the United States.

The French newspaperd Le Monde recently printed an article quoting speculation that South Korea might use Kim's fate a bargaining chip to obtain an unequivocal recognition of Chon's government by U.S. officials.One government official recently called an American reporter's attention to the article several times in the course of an interview. He refused to say, however, whether such a bargain was, in fact, the government's strategy.

Another official close to Chon said the former general will try to maintain amicable relations with the United States, but would strongly resist American attempts to influence such issues as the trial of Kim.

"He will not like it for Americans to tell him what to do and what not to do in the Kim Dae Jung case," he said.

Since the troop withdrawal was suspended, the United States has had little leverage, and it has foresworn using economic pressures such as the cessation of loans from the U.S. Export Import Bank. Minor pressures have been exerted, such as a long delay in scheduling a joint U.S.-South Korean military consultation, but observers here do not believe they have much effect.

The State Department also has expressed concern about the South Korean military involvement in politics, and has called repeatedly for a government with a "broad base of support" resulting from early elections. Just what would constitute a broad base has not been defined.

It is expected that the new constitution will propose indirect presidential elections through some electoral device similar to the National Conference for Unification. Whether the country is to have political parties and an independent national legislature is unknown.

Government officials, however, have made it clear that freewheeling, Western-style elections and independent parties are not likely to emerge anytime soon, and have hinted that some form of electoral management will be done by the government.

One official said it would be "many years" before South Korea has fully popular elections, insisting that "South Koreans are too emotional for that." The official acknowledged that this would require restraints on dissidents who want totally free elections.

"Not for many years will Western-style democracy work here," he said, adding that the United States should not attempt to use its military presence or any other pressures to achieve that type of development.