And since 9/11, the workloads have grown heavier. Scores of officers, traumatized and stung by the loss of so many comrades, turned to the chaplains for solace, guidance and a prayer. Father Romano, for one, spent 10 months at ground zero and accompanied the body of every recovered officer as it was carried out of the pit.  Police Commissioner Raymond W. Kelly says the stigma that once kept many officers from seeking out a chaplain, lest they be seen as frail, has largely faded since 9/11. "The shock waves were huge throughout the entire department," he said. "For the first time, people saw the organization as a big nurturing family and seeking help was no longer a sign of weakness."  The chaplains, on call 24 hours a day, reflect the department's increasing diversity: there is the Rev. Luis Serrano, a Hispanic Pentecostal minister, the Rev. Dr. Suzan Johnson Cook, a black Baptist and the first female chaplain, and Iman Izak-El Mu'eed Pasha, the unit's first Muslim religious figure who recently retired. (His replacement is being sought).  With their standard-issue navy blues and lapels glinting with insignia, the chaplains are, at first glance, indistinguishable from the rank and file. But they do not carry weapons and wherever they go, they are swept up in the embrace of high-ranking commanders, pimple-faced cadets and civilian 911 operators.  "I'm not Jewish, but I want this guy to do my eulogy," Detective Stephen Giaco said jokingly after giving Rabbi Kass a hug in the Midtown North station house where he works. "That's because he'll make me sound like a better person than I really am."  Chaplains have the power to pick up a phone, call a commanding officer and wrangle out a resolution to a personality clash. They are also sworn to secrecy, something they tell each new class of police recruits.  "We're a shoulder to cry on and a sympathetic ear but a lot of what we do is troubleshoot for the officers," said Ms. Johnson Cook. "We can cut through the red tape. And when it comes to the African-American community, sometimes I serve as a cultural translator."  With four decades on the force, Rabbi Kass is almost as recognizable around police headquarters as his boss, Commissioner Kelly. He is also a frequent presence at churches, mosques and Hindu temples. "If there was an entry in Guinness Book of World Records for the rabbi who attended the most Catholic Masses, I would win hands down," he said with a boyish grin.  Rabbi Kass has had a colorful run: there were the death threats that earned his family months of round-the-clock security and a starring role in a hostage crisis that was resolved with a pastrami sandwich. Rabbi Kass persuaded the self-identified Jewish hostage-taker to exchange his guns for two Carnegie Deli sandwiches. Another mark of devotion to the job? He left his own son's bar mitzvah when he got word that an officer had been shot in the line of duty.  Addressing a class of police academy students this week, the rabbi lectured the recruits about the lures of graft, the temptation to prejudge those of other ethnicities and, more profoundly, an officer's power to take away life.  "You are the only ones in society that can use lethal force," he said. "None of you should ever shoot your gun lightly. And if you do, it should be done with great reluctance and sadness. It is when you shoot and not think twice, that you have lost your humanity."
New York City police chaplains, whose functions were once largely ceremonial, now serve as therapists, confidants and spiritual leaders; workloads have grown heavier since 9/11 as scores of traumatized officers turned to chaplains for solace, guidance and prayer; chaplains include rabbi, Roman Catholic priest, Pentecostal minister and black female Baptist, and replacement is being sought for retired Muslim imam, all reflecting increasing diversity of police force; photo of Rev Luis Serrano, Rabbi Alvin Kass and Rev Robert Romano at officer's funeral (M)