Despite early attempts to put forth a united front, with many incum bents agreeing for the first time to run as a slate, Montgomery County's Democratic party is wracked by some of its wildest and bloodiest infighting in two decades.

Two days before the primary, most of the candidates in contested Democratic races in the "good government" county have engaged in name-calling, charges of dirty tricks, calls for ethics investigations, and complaints that campaign posters have been stolen, defaced and even burned.

"This is a dirty campaign, just awful," said State Sen. Victor L. Crawford. "What's so ironic is that when this is over, these people are going to have to run together. I don't know how they're going to do it, there's so much bad blood. It's the most divided in 20 years. "

Making matters even more confusing, a dozen slates and endorsing groups each have mailed out their own sample ballots to democratic voters. "It's a mess," said Crawford, who is not seeking reelection, and has not taken sides in the most divisive of the races, for the County Council.

While the incumbents running for county executive, courthouse, the Legislature and Congress agreed to bury their differences to run together, signs of disarray are widespread:

* In the 16th Legislative district, two strong challengers, Gilbert Genn and Abbe D. Lowell, are waging seperate assaults against incumbents Nancy Kopp and Marilyn goldwater and their running mate, Steve Nassau. Genn and Lowell have complained that more than 100 campaign posters were ripped down over the Labor Day weekend.

* In the 18th Legislative district, challenger John Hurson has won support from about half of the precinct organization in his bid to unseat one of the incumbent delegates. County Executive Charles W. Gilchrist has intervened in the increasingly bitter race with a personal letter as part of a last-minute mass mailing in behalf of incumbents Patricia Sher, Donald B. Robertson and Helen Koss. But Gilchrist ended up antagonizing his own precinct workers who were supporting Hurson and angering his County Council running mates.

* Even the traditionally low-profile courthouse race, particularly for sheriff and clerk of courts -- have been made visible by tough primary challengers taking on long-entrenched incumbents. Police officer Tony Fisher has been gaining publicity with his strident accusations of incompetence against Sheriff Jim Young, and Ruth Vurek has run a high-profile campaign against clerk Howard Smith.

* Nowhere is the disarray reflected more than in the bitter fight for the seven seats on the County Council.

After attempting to forge its own incumbents' slate, the council members broke down into two factions: The Merit Team headed by council members David Scull and Esther Gelman, and the United Democrats headed by council president Neal Potter and backed by Gilchrist.

Among other things, both sides have accused the other of trying to mislead the public with its advertising and literature.

Past feuds in the county have been born out of ideas, differences over land-use and zoning, Liberal versus conservative, party boses against reformers, but the current fight appears to have grown out of mutual antagonism between Gilchrist and Gelman.

From the beginning of Gilchrist's administration, Gelman -- who did not support Gilchrist in the 1978 primary -- took on the role of watchdog over the new executive. She challenged some key Gilchrist appointments and blocked his attempt ot move the park and planning commission to Rockville. She claimed she was trying to preserve the council as a check on the executive. But Gilchrist and his allies took it as a personal and political affront.

The Scull/Gelman "Merit Team" refers to its opponents as "the rubber stamp slate" of an executive branch that wants to gut the county's civil service system.

The Potter/Gilchrist "United Democrats," not to be outdone, call their opponents "the Demerit Team" comprised of headline hunters who want to grab credit for popular bills while disregarding council procedure.

Scull contends the real division $1between the two sides is philosophical--over the future role of the council in its relations with the executive branch. That split was reflected, Scull says, in a recent vote over a charter amendment that he had authored that would have given the council additional power in shaping future county budgets if federal funds to the area are reduced. Potter's side killed that proposal, saying it was ill-prepared and unneeded.

The Merit Team has made that vote its cause celebre, calling it an example of how the current council majority panders to executive authority. The United Democrates use that same defeated amendment ot point up how they say the Merit Team members don't do their homework and then distort facts to make their case in the press.