For nearly 10 years, this Portland sextet has written, rehearsed and performed as a cohesive whole. But as of last month, transition has become the operative word for the authorities on dynamic funk.

In December, Rustic Overtones drummer Tony McNaboe told his band mates that he was leaving the band. A week later, saxophonist Ryan Zoidis announced he was departing too. Both had been with the band since the early ’90s.

“It was a really weird time for them to leave because everything was going so well for us,” Rustic keyboardist Spencer Albee said in a recent phone interview.

The band had just released its second single off its newest album, “Viva Nueva,” and album sales were increasing. Their label, Tommy Boy, was “treating them great,” Albee said, and they were getting ready to record another album.

“We were more confused by their departure than anything,” Albee said. “It seemed odd.”

There wasn’t a big falling out – “no one was shot in the foot,” Albee said – the parting members were just ready for a change.

“Tony’s pursuing music of a more spiritual nature,” he said. “But he’s a great songwriter and singer so you’ll hear from Tony again – he’ll just be wearing a different hat.”

Zoidis left for similar reasons.

“He was interested in playing music more centered in jazz and instrumental funk,” Albee said. “He, like Tony, could easily lead his own band.”

Down from six members to four, Albee, Dave Gutter, Jason Ward and Jon Roods all took a step back.

“We caught our breath and wrote some songs,” Albee said. “Then we decided, first things first, we need a drummer.”

The band auditioned 25 drummers, ranging in age from 16 to 40. Musicians came from Bangor and as far as Raleigh, N.C., to audition.

Three were called back for a second audition. They each were told they would hear from them the next day.

At midnight, the band members grabbed a phone and placed a call.

Marc Boisvert, a 27-year-old drummer and bartender, picked up the phone.

“I had my cell phone on me in my truck and they called me and said ‘congratulations, you’re in,’ and I almost ran off the road,” Boisvert said in a recent interview. “I hadn’t slept for weeks, that’s what getting this gig meant to me.”

Boisvert started playing the drums when he was 11 years old after seeing musician Buddy Rich perform.

“I knew that what I wanted to do the rest of my life was play drums,” he said.

Boisvert started listening to Rustic when he came to the state five years ago to attend the University of Southern Maine. He said he’s been a fan ever since.

“I have to step back and pinch myself sometimes because now I’m playing with them,” he said. “My life changed in a heartbeat … and now I’m living my dream. I’m very appreciative because there are a lot of good drummers who could have gotten this gig.”

But Albee and the others had faith that Boisvert could hold his own.

“We didn’t want to replace Tony with someone who played like Tony because he is a unique drummer with a unique style,” Albee said. “Marc was the most versatile and the most professional. We call him the human drum machine because his timing is so fantastic.”

But Boisvert wasn’t the only one with perfect timing. While the band members were auditioning drummers, 18-year-old Keith Reynolds of Winslow decided to tag along with one of his friends who was auditioning.

The members started chatting with Reynolds as his friend set up. As it turned out, Reynolds plays the saxophone and he had some of his CDs on him.

“We listened to him and said, ‘this guy is great,'” Albee said. “We didn’t even audition him, and we called up and said, ‘if you want it, you’re in.'”

Reynolds, who still is a senior at Waterville High School, jumped at the opportunity.

“I was pretty much flipping,” Reynolds said Thursday. “This is the kind of thing you really dream about.”

To Reynolds’ surprise, his parents supported his decision to join Rustic, and he was able to work out a deal with his school so he still can graduate. He is fulfilling his two remaining requirements through correspondence with his teachers.

Reynolds was planning on attending music school after graduating but said he is deferring his acceptance for at least a year.

“It’s an adrenaline rush to be on stage and I wouldn’t want to be doing anything else right now,” he said.

“It’s funny how we turned from your average bunch of kids jamming in someone’s garage to an educational institution,” Albee said, chuckling.

In a matter of four days, the band rehearsed with the new members, ran through the set and packed the van and headed to Washington, D.C., and played at the 9:30 Club.

The band wanted to see if the two new members would crack under all the pressure.

“We need people who can keep their cool so we put the squeeze on someone right out of the gate and roll everything up into one enchilada,” Albee said.

Boisvert said it hasn’t been a problem.

“I’ve been gearing my entire life for this moment and I love every minute of it,” he said. “I love traveling and seeing the road. I love sweating my ass off on stage because that’s what drummers do. I love my new lifestyle. This is what living is all about – doing what you want to do.”

And the crowds seem to enjoy the change, Albee said.

“I expected more of a serious backlash like, ‘where are the old guys?’ but people have come up and said that the drummer is great – not even knowing that he’s new,” Albee said.

“With new blood in the band comes a new energy,” he added. “For us it’s been nothing but a positive experience and the crowd is pleased.”

And fans will have another reason to be pleased. Rustic hopes to release another album this summer.