When Brazilian President Ernesto Geisel named Gen. Joao Baptista Figueriedo as his successor early this year, the action was interpreted as proof of Geisel's political strength and personal prestige. For the first time since the military seized power in a coup 14 years ago, a president was able to hand pick his successor.

By breaking with tradition and by-passing the customary consultations with the military high command, however, Gen. Geisel inadvertently may have weakened the position of his heir apparent and encouraged his military critics. The Figueiredo nomination continues to encounter resistance within the armed forces, with both liberal and hard-line elements actively expressing their opposition.

No one here goes so far as to suggest the possibility of a coup to prevent Figueiredo from taking over. But Geisel's decision clearly has divided the armed forces and observers here see resentment within the ranks as increasingly worrisome for Geisel an his protege, whose six-year term is to begin next march.

"Geisel has got himself caught in a real cross fire," one foreign military analyst said. "But in another few months he can duck out. In the end, the problem is going to have to be resolved one way or another by Figueiredo."

The boldest manifestation thus far of military discontent with Geisel's actions came in March, when Col. Tarcision Nunes Ferreira, commander of an armored infantry battalion in southern Brazil, attacked Geisel in a speech and newspaper interview for "usurping" power and "disdaining" military opinion.

Ferreira, considered a liberal who favors a return to democratic rule, further charged that the true character and purpose of the military has undergone a "deformation" since the 1964 coup.

"We left behind a totalitarian process attempted through disorderly government in favor of a totalitarian process carried out by the government through an excess of order," he said.

Coupled with this denunciation of Geisel and his government was frank criticism of the Figueiredo nomination. Ferreira argued that Figueiredo was being viewed "negatively" within the armed forces and that while he had nothing personal against Figueiredo, "what no one can swallow is the process by which he was selected."

The Ferreira interview has caused shock waves in both civilian and military circles, as much for its having occurred as for its content. For the first time in nearly a decade, noted Veja, the nation's leading news magazine, "an active officer below the rank of general and in a troop command post has dared to criticize publicly the lines of official policy."

Following his remarks, Ferreira was removed from his post and placed under house arrest, along with the reporter who interviewed him. That order has since been lifted, however.

"Geisel can't really afford to come down too hard on Ferreira," said a European diplomat here. "If he does, he'll be alienating the liberals in the military, who are the very same people his boy Figueiredo is going to need as a counterweight to the hard liners."

Figueiredo has long been opposed by the hard-line faction, which views him as committed to Geisel's program of "decompression" aimed at gradually restoring liberties. His unpopularity rose dramatically last October, after Geisel fired army minister Sylvio Frota, the hard-liners' favorite in the behind-the-scenes manuevering for the presidency.

According to press reports here, when Frota learned of his impending dismissal, he tried to mount a coup against Geisel. When that failed, he issued a manifesto blasting the Geisel government for being soft on communism and subversion, singling out Figueiredo's national intelligence service for some of the harshest critism.

In January, Geisel's chief liaison to the armed forces, Gen. Hugo Abreu, resigned to protest the Figueiredo nomination. Abreu, who is known to have strong ties to the strongly nationalistic Frota group, reportedly told Geisel that "the army does not support" the Figueiredo choice and accused some close Figueiredo associates of corruption and links to multinational corporations.

"The Figueiredo government is going to be a very difficult time militarily," predicted Carlos Chagas, who served as press secretary to President Arhtur da Costa e Silva during a turbulent period in the late '60s and is now a leading political columnist.

Figueiredo, in a recent interview, admitted that he is playing a weak hand and warned that "the military is not ready" for an opposition party victory in congressional elections this fall. If that happens, he argued, hardline forces will make "the thing explode. Either I get blown up along with it, or else I go along with them and we head into aregime far worse than this one.