With far less oppostion than greeted President Cater's plan to overhaul the civil service, the Montgomery County government has been making some of the same fundamental changes in the salary system for its 6,500 employes.

Under a plan scheduled to take effect July 1, the country will tie pay raises more closely to job performance and eliminate automatic increases based solely on the amount of time an employe has worked for the country.

In addition, a revised retirement program to cover employes hired after July 1, will substantially reduce retirement benefits for hundreds of country workers.

When the new retirement and salary systems go into effect, country officials say, the government will save hundreds of thousands, and eventually millions, of dollars annually. At the same time, employes will lose thousands of dollars of salary during their working lives, and in some cases, will also retire on reduced pensions.

Nonetheless, employe opposition to the new programs has been surprisingly muted. Employe unions have expressed some dissatifaction with the revisions and the largest employe union is urging current employes not to join the new pension plan. Several employes have indicated they would rather have larger paychecks now than put money aside for retirement.

One of the chief reasons for the changes was that the existing salary system "rewarded mediocrity at the expense of the real chargers," said Ron Lloyd, country personnel director. "If you know everyone is going to get rewarded for job performance equally, folks being folks, why do better than averages?"

Country Executive James P. Gleason added, and his chief aides contend, that curtailing salary and pension payments - which currently represent about one-fifth of the $568 million budget for next year - is a key factor in controlling government costs.

"The costs are going out og sight," Gleason said, throwing up his hands during an interview. "It's much better to take reasonable precautions now."

Under the new pay plan, the automatic yearly salary increases of 5 per cent, to which most employes have become accustomed as they progress up the pay scale, will be reduced to 2 per cent and granted uniformly to all 6,-500 employes affected by the program.

Police, librarians and other country government workers are affected by the new plans, but the country's 7,000 teachers are not.

In return, employes will be guaranteed annual cost-of-living raises adjusted to inflationary growth in the metropolitan area. Employes in the past have had to bargain with the Country Council for cost-of-living raises, but increasing fiscal demands have prevented pay raises consistent with rising inflation in the metropolitan area.

Any dissension from Montgomery employes has been muted in part oy the country's response to their repeated appeals for relief from the persistent inflationary bite.

In addition , the effect of the changes will be gradual, in part because the new salary sales will be phased in over the next two years.

Yet, the Montgomery Country Government Employes Organization has also warned that new employes and those anticipating several more promotions in their careers will be hard hit by the changes.

"It's a shame," said Mark Wulff, a 30-year-old computer analyst-programmer, who has calculated that he will lose roughly $10,000 to $20,000 during the rest of his career with the country.

"Something like this sends fingers out throughout the entire financial system," said Wulf. "A brand new employe could lose as much as $25,000 to $30,000 in actual cash, plus interest, over his career. That could draw a lower caliber employe who is willing to work for less."

The new pay plan, however, will increase the annual earnings of some employes who have reached the top of their grade and under the old system could count only on annual cost of living raises to boost their salaries.

Reaction to the new retirement system among union officers and country employes interviewed recently was somewhat more negative than the reaction to the new pay scales. A few employes did say that their present contributions to the pension system are too hogh in light of the immediated cash needs.

Others, however, objected to the reduction of new employes' eventual pension payments.

For all new employes and current workers who choose to join the plan, the revised pension system will reduce most employes' contributions from 6 to 3 percent of each pay check, thus increasing take-home pay. But benefits from the country's pension fund will be reduced after the age of 65, when workers are eligible for full Social Security reimbursement.

That reduction will mean that a 20-year employe earning $16,000 would receive on retirement only a $3,200 annual pension (in addition to Social Security) under the new formula instead of the $6,400 the worker would have earned under the current scheme.

As an incentive to existing employes, the country is offering those who elect to join the optional program an immediate cash refund equal to the amount they have paid into the pension fund since they became country employes.

This system is designed to save tax-payers $50 million over the next 20 years, said chief country addministrator William Hussman.

Montgomery officials drew their new pension formula from proposals for a sweeping revision of the state pension system during this year's Maryland General Assembly. But while sponsors of state pension revision were opposed by powerful employes unions and failed to win the legistature's approval of their plan, the Montgomery administrators, supported by the Country Council, succeeded.

While Hussman hopes that half the country employes join the new pension system within two years, the Montgomery Country Government Employee Union has urged its 3,800 members to keep out.

"While don't know what effect this will have on most people," said Jack Jardeleza, an auditor who heads the employes' organization. "You get out of it what you put into it and that means less money when you retire.They're taking away what we consider our vested retirement rights."

Yet some employes, including several police officers, approve of the plan, and the police officers union did not officially oppose the change so long as entry into the new pension fun remained optional.

"It's a gamble," said Lenny Simpson, president of the police union. "Some officers say they don't think they'll live past 65, and they need the cash now to support their families."

The country administration is banking on such employes who in Wulff's words, "are focusing on the right here and now because of the annual inflationary bite, with the assumption that society will take care of them when they retire."