Newly appointed Montgomery County Police Chief Bernard D. Crooke Jr. said yesterday he does not expect to move quickly to make changes in the county's police department. He first priority will be winning the confidence of the rank and file.

In stating his goals. Crooke appeared to be fulfilling the wishes of County Executive Charles W. Gilchrist who sought a police chief who would bring stability to the 728-member department and improve police morale after the tumultuous two-year tenure of Robert J. diGrazia.

During his administration, diGrazia found himself in frequent disputes with his officers over his liberal policies and flamboyant administrative style. Last summer, a majority of the rank and file voted "no confidence" in diGrazia; Gilchrist fired him shortly after taking office in December.

In contrast to diGrazia, who began reorganizing the department and implementing new programs soon after he arrived, Crooke said, "Some of the most courageous decisions I've seen made were decisions not to implement anything (new)... A lot of police executives feel they have to do something (new) or else they won't be considered a progressive police chief.

"To make changes for change's sake is foolish" Crooke added.

The 45-year-old Crooke is a 23-year police veteran who currently is the number two man in the District of Columbia police department. The son of a D.C. homicide detective, he moved up through the police ranks quickly from street patrolman to investigator, 3rd District commander and director of planning and development.

As an assistant police chief in Washington, Crooke is in charge of the day-to-day operations of the city's 4,170-member force, overseeing all police activities from criminal investigations to routine patrol. He is a native of Washington who has lived most of his life in Montgomery County.

Although both Gilchrist and Crooke avoided any references to diGrazia, certain contrasts in both the style and the philosophy were evident.

Gilchrist fired diGrazia in part because of remarks the ex-chief had made about police officers, such as a statement deGrazia made at a public forum shortly before he was fired that most police officers "see the community as the enemy."

Yesterday, Crooke was effusive in his praise of the Montgomery department, stressing the officers' "quality" and "compassion."

Whilh diGrazian made a national reputation promoting the philosophy that police officers should be "social workers with guns," Crooke stressed yesterday that the primary mission of a police officer is still to fight crime.

"Out of neccessity," he said, police officers do some social work because the police department is open 24 hours a day, every day, and "people call the police when they have a problem that really belongs in another agency.

"The social ills of any community become the police department's problims and police departments have to know how to cope with this," Crooke said.

Although he says he supports the kind of human relations training that diGrazia wanted to make a primary part of officers' instruction, Crooke said he thinks actual street experience "is the best teacher."

Officer Robert McKenna, president of the county Police Association, who complained earlier this week that his group and the Fraternal Order of Police (FOP) were not consulted on Gilchrist's choice, said after hearing Crooke yesterday: "I was impressed with his down-to-earth manner, the fact that he came up through the ranks and the fact that he was a little nervous" at the news conference.

Lenny Simpson, president of the FOP, said Crooke has a reputation for standing up for the officer on the beat. "The only problem is this department has just gone through a bad experience with someone (diGrazia) who said the same thing. The men are going to be very reluctant to listen. They'll want to see action."

Crooke praised Maj. Jonald E. Brooks, whom diGrazia had tried to fire and who has been running the department since December.

Brooks, Gilchrist and County Chief Administrative Officer Robert Wilson have removed two of diGrazia's most controversial appointees, Philip H. Marks the civilian who was diGrazia's closest adviser, and Phyllis McDonald, the first woman and cvilian to head the police training academy.Marks is now working in the county budget department. McDonald has been replaced by a police officer, She has filed a grievance against the department.

Crooke said he believes there is a place for civilians in the department, but thinks the training academy should be headed by an officer.

Crooke will take over as chief by the end of April, he said. He is retiring from the D.C. force with a $20,000-a-year pension and will be paid $48,000 a year in Montgomery.