In the month since president Jaafar Nimeri was overthrown, the Sudanese have rewritten the text book for political change in the Third World.

From the start, the process has been refreshing -- if sometimes confused and infuriatingly slow -- as they doggedly try to set back the clock to the perhaps idealized days of parliamentary democracy in the 1960s.

But it is precisely that trial-and-error approach that sets the experience apart and justifies the Arabic name -- infitidah, or shaking off -- for what has happened in the wake of Nimeri's increasingly chaotic 16-year rule.

A month ago, the professional elites with great dignity demonstrated in Khartoum streets until, on April 6, they forced the reluctant armed forces to take over.

Most striking, then, was what was left out of the usual formula.

The coup leaders did not call themselves a "revolutionary command council" or proclaim themselves a "corrective movement." In fact the word "revolutionary" remains conspicuously absent from their vocabulary.

Similarly, when they seized the radio station, they had no Communique No. 1 prepared for instant broadcast, naming a new government and justifying their takeover with a list of promised, if vague, reforms.

Now, every night in the Khartoum area, after the 100 degree-plus heat of the day abates, Sudanese flock to open-air rallies of parties that only recently emerged from hiding. The crowds follow the speeches with all the fervor of a people long deprived of the give and take of democratic dialogue. Even hecklers are tolerated.

But many Sudanese remember that after independence from British rule in 1956, the political parties were much to blame for government instability that led to military rule in 1958 under field marshal Ibrahim Abboud for six years, then to Nimeri's own takeover in 1969.

This time, some members of the Sudanese elite are determined to avoid past errors.

Think tanks have formed among the professionals who spearheaded the final opposition to Nimeri, helping to ensure that the transitional government stays on track until elections are held in a year.

These watchdog groups are outspoken in their criticisms of their fellow professionals and other civilians. They note that it was because of civilians' dithering in the critical days after the coup that Army leaders felt obliged to set up the now-ruling Transitional Military Council to fill the power vacuum.

Also worrying is the knowledge that Iraqi and Libyan money is pouring in to finance various political parties. In general, the parties tolerate the interim civilian government out of a desire to get on with their own campaigning and to avoid responsibility for Sudan's enormous problems.

Many Sudanese forewarn that things are bound to get worse before they get better. That means more famine, chaotic economics and the likelihood of no quick solution to the insurrection in the south, which is sapping public finances and confidence.

Undeterred, the watchdogs sound determined to step in and scale down wage demands expected from among the more than 150 trade unions that now are members of the original anti-Nimeri alliance of six professional groups and three political parties.

So far, most foreign help is dictated by fear. Red Sea neighbor Saudi Arabia was so concerned that less moderate men might seize power that it has supplied more funds than in the final Nimeri period.

Soon after the coup, a Sudanese military delegation received a $50 million check from the Saudis and $62 million in oil credits that, along with $82 million previously committed by Washington, should keep chronically strapped Sudan in petroleum products through August.

But how Sudan, with foreign debts of $9 billion, will work out its salvation with its western creditors and the International Monetary Fund remains a mystery.

Until Sudan can scrape together $120 million to pay its IMF arrears, few donor countries are expected to produce extra funds that some of them are considering to bolster the return to civilian rule.

But with politicians denouncing the IMF somewhat inaccurately as having allowed Nimeri to ruin the economy, even optimists predict that it could take months before the new authorities accept the knowledge that only long-term economic and financial austerity can start Sudan on a slow and painful road to recovery.

The public and officials console themselves with rectifying the errors of the Nimeri era, an essentially inexpensive enterprise.

With calm and thoroughness, the authorities are investigating corruption and wrongdoing. Unconfirmed reports insist that various Nimeri middlemen now under arrest are offering to exchange their ill-gotten gains for a ticket out of the country.

High on the public list for investigation is the case of the Falasha refugees, the black Ethiopian Jews Nimeri allowed to be flown out of Sudan with the aid first of Israel and later of the United States.

All political parties demand an explanation of the U.S. government role in this clandestine operation. A common theme is that Nimeri, as an Arab leader, should have had no part in secret emigration to Israel -- although some intellectuals recall that other Arab countries allowed their Jews to leave.

The public also is fascinated by unconfirmed rumors that Nimeri and key officials were paid $1,700 for each Falasha emigrant. Bankers reported the sudden appearance of fresh $100 bills in plastic packets containing $100,000 in December and again in March, periods coinciding with the Falasha airlifts.