Three days of intense talks between top Vatican officials and rebel French Archbishop Marcel Lefebvre indicate that despite innumerable problems, both Pope John Paul II and the traditionalist prelate are eager to end the four-year dispute that has threatened to divide the Roman Catholic Church.

A Vatican spokesman this week described the issues separating Lefebvre from the rest of the church as "doctrinal, disciplinary and pastoral." The 72-year-old archbishop was suspended from his priestly duties by Pope Paul VI in July 1976 after refusing to accept papal authority.

Since that time he has continued to defy the Vatican by persisting in saying mass, preaching and ordaining priests at his seminary in Econe, Switzerland. The last six ordinations -- out of a total of 62 -- came only a few weeks after Lefebvre was received, and reportedly embraced, by the pope in a private audience on Nov. 18.

Nevertheless, the Polish-born pontiff is apparently willing to consider making certain concessions to bring traditionalists such as Lefebvre back into the fold. Since his election on Oct. 16, John Paul has made it clear that one goal of his fledgling pontificate is the reestablishment of unity in the Roman Catholic world with both conservatives and progressives.

A reconciliation with Lefebvre has been opposed violently in recent years by French bishops, who tend to see him as an incorrigible reactionary.

Vatican conservatives, however, favor a reconciliation, which could modify the prevailing liberal interpretation of the reforms of the 1962-65 Second Vatican Council.

The principal mediator who arranged the November meeting between Lefebvre and the pope was conservative Cardinal Giuseppe Siri of Genoa.Siri has accepted the conclusions of the Vatican Council but has been an outspoken critic of some of its principles. He reportedly persuaded Lefebvre to accept the authority of both to accept the authority of both the pope and the Council in exchange for an audience with the pope and a new dialogue.

The rupture between the archibishop and the Vatican began in 1974 when Lefebvre published a book entitled "A Bishop Speaks" in which he challenged the concept of papal infallibility, and various rulings of the Council, particularly those regarding ecumenism, religious freedom and liturgical reforms.

Subsequently he also spoke out against left-wingers in the church, accused Pope Paul VI of being soft on communism, and compared liberal members of the Vatican governemnt, the Curia, to "servants of Satan."

Lefebvre arrived here Tuesday night from Switzerland and since Wednesday has spent several hours each morning answering questions put to him by members of the Vatican's Holy Congregation for the doctrine of the Faith.

Although Lefebvre has said he will not retreat from his convictions, he said he is optimistic about the outcome of the talks.

Deciding the issue will be the 11 cardinals of the Holy Congregation and ultimately the pope. After Lefebvre's questioning ends next week the cardinals will study his dossier and their prefect, Yugoslav Cardinal Franjo Seper, will report to Pope John Paul, probably after his return from the Latin American Bishops' Conference in Mexico.

One major obstacle to an agreement is the future of Lefebvre's reportedly wealthy "Priestly Brotherhood of Saint Pius X," which has set up branches in Europe, in Latin America and in the United States.

Another is whether the Vatican will allow the modern and traditional rites of mass to coexist and accept Lefebvre's ordinations.

Despite these difficulties, there is a feeling here that the pope is determined to give the controversial French prelate every opportunity to reach an agreement. For his part, Lefebvre's openness to dialogue seems to reflect a feeling that the doctrinally conservative John Paul II is a different kind of pope than his two predecessors.