Jonathan Cain was not surprised when his bandmate Steve Perry wanted out of Journey – for a second time.

It was 1998 when the frontman, known as "The Voice" due to his powerful pipes, left the band for good. The group had soared to stardom during the 1980s with epic, sweeping tracks like "Don’t Stop Believin’," "Faithfully" and "Open Arms." 

"He was fragile," the keyboardist, 73, recalled to Fox News Digital. "When we got back together, I could tell he was in a fragile place. Physically, he was starting to get aches and pains. His voice wasn’t quite where it was years ago. He was a little leery. I think it had all taken a toll on him, after all those years."

The band is the subject of a new documentary airing Sunday on Reelz, titled "Journey: A Voice Lost . . . and Found." It explores how the group dominated the American music scene with their arena anthems and power ballads – and how Perry walked away at the height of their success.

The group journey leaning against each other and smiling in a promo photo

From left to right, Jonathan Cain, Steve Perry, Neal Schon, Ross Valory and Steve Smith of the rock band Journey pose for a picture. (© Roger Ressmeyer/CORBIS/VCG via Getty Images)

The burned-out singer, yearning to be out of the glaring spotlight, originally left in 1987, The New York Times reported. In 1996, he reunited with his bandmates, resulting in a radio hit with the Grammy-nominated romantic ballad "When You Love a Woman."

Steve Perry wearing a yellow shirt and singing on a mic

Steve Perry originally walked away from Journey at the height of their fame. (Larry Hulst/Michael Ochs Archives/Getty Images)

A tour was planned. A second act for Journey looked promising, but that all soon changed.

It was around that time that Perry took a long hike in Hawaii and suddenly felt a sharp pain in his hip while reaching the top of a mountain. The singer, then in his mid-40s, learned that he had a degenerative bone condition that required hip-replacement surgery, Rolling Stone reported. According to the outlet, Perry attempted alternative treatments to avoid going under the knife, but he was still struggling.

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A close-up of Steve Perry singing wearing a blue shirt

Steve Perry was suffering from physical ailments after he reunited with his band. (Tim Mosenfelder/ImageDirect)

Perry claimed to the outlet that the band wanted him to make a decision about the surgery quickly. Journey eventually hit the road. Perry returned to living a private life as he focused on his health.

"I think we made a really good record, ‘Trial By Fire,’" Cain reflected. "We had some great moments. But I could tell he wasn’t gung ho to go out there again. He only just wanted to do four shows and call it a day. I think [guitarist] Neal [Schon] was the one who convinced him to do a whole album. And he had a wonderful time at the studio. But when it came time to talk about touring, I could tell he was not up for it, physically and emotionally."

Steve Perry and Neal Schon playing guitar to each other and smiling

Steve Perry, left, and Neal Schon performing in San Francisco, circa 1978. (Ed Perlstein/Redferns/Getty Images)

For Journey, the show had to go on. They recruited Steve Augeri as a replacement for Perry, unleashing fury among die-hard fans. In the documentary, Cain said he received threats from those who insisted Perry was irreplaceable.

Steve Agueri in a white shirt performing on stage

Journey singer Steven Augeri performs at Shoreline Amphitheater in Mountain View, California, on Aug. 10, 2001. (Tim Mosenfelder/ImageDirect)

"It was a big blowback," said Cain. "Some felt Journey wouldn’t be Journey without Steve Perry. That’s certainly one of the opinions that’s out there. But you know, I felt that the music was bigger than us. . . . But the fans objected. . . . They had to see it to believe it. And Steve was game for the job. He showed up and did an admirable job. He was a great entertainer and gave us eight solid years. And the ladies loved him. But in the back of my mind, I wondered, ‘What if something horrible happened? What if somebody brought a gun?’ They would leave nasty messages on my phone machine."

Jonathan Cain wearing a sleeveless blue shirt while playing the keyboard

Jonathan Cain said he received threats from angry fans after word got out that Journey would replace Steve Perry. (Paul Natkin/Getty Images)

"I had to change my number three times," he continued. "There was a lot of anger. The fans thought we kicked Steve out, which was not true. . . . He just didn’t want to do it anymore. He was going through physical pain. . . . And it can be excruciating. All that extreme traveling and lifestyle just drains your body from the ability to heal. I think with years of touring, you pay a price for it physically. . . . It can take a toll. . . . I think Steve felt it was time to get off the train. And he’s a personal guy. He likes his personal life."

The fans needed plenty of convincing, Cain admitted.

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Jonathan Cain and Steve Augeri smiking in black shirts

Jonathan Cain, left, said he supported Steve Augeri, right, as a replacement for Steve Perry. (Dimitrios Kambouris/WireImage)

"Change Is hard," said Cain. "If change was easy, it wouldn’t be worth it. And at the time, our manager was very confident that we could be Journey without Steve. Neal and I had written these songs that really sounded like Journey, and Steve Perry was nowhere to be found. We wanted to prove ourselves. It just took time to get there."

Looking back, Cain said there are no hard feelings.

"I don’t have anything bad to say about Steve," he said. "He might have his difficult ways. He’s eccentric in a lot of ways. But he wanted a private life. And he was always fair with me. He was a great bandmate and a great band leader."

Steve Perry embracing Jonathan Cain at the Rock and Roll Hall of Fame

From left to right, inductees Neal Schon, Steve Perry and Jonathan Cain of Journey accept an award onstage at the 32nd Annual Rock & Roll Hall of Fame Induction Ceremony at Barclays Center on April 7, 2017, in New York City. (Kevin Kane/WireImage for Rock and Roll Hall of Fame)

Cain said the last time he and Perry exchanged words was at the Rock ‘n’ Roll Hall of Fame in 2017, when Journey was inducted. Perry, now 74, did not sing.

The quest for a new singer resumed after Augeri's departure. While scrolling through YouTube videos, Schon came across Arnel Pineda, a 45-year-old Filipino club singer who did Journey covers. A stunned Pineda was flown to the U.S. from Manila to join Journey. He perfected his English by reading newspapers and using a dictionary to look up words he did not understand. In 2007, Journey announced Pineda as their new singer. He soon won over skeptical audiences.

Arnel Pineda performing on stage and looking surprised

Arnel Pineda was discovered on YouTube. (Ethan Miller/Getty Images)

"You could tell he had the pipes," said Cain. "[But] . . . he had to learn 20 years of Journey and sing it in a couple of weeks. He didn’t have a lot of studio chops. But he stepped up to the game. . . . I coached him through it. I made sure he was going to the gym every day to get that lung power. I got him a dialect coach. He studied the lyrics, and we sang in the evenings. We changed a lot of things about his approach to singing Journey. And then we threw him in the lion’s den, so to speak, for his first performance. And he did an exceptional job."

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Arnel Pineda and Neal Schon performing on stage

Arnel Pineda, left, and Neal Schon perform during Journey's 50th Anniversary Tour at Moody Center on Feb. 22, 2023, in Austin, Texas. (Rob Loud/Getty Images for Journey)

Today, Journey are celebrating their 50th anniversary and have been touring with Pineda, 55. In 2018, Perry released a solo album, "Traces," with a deluxe version debuting in 2019. In 2021, he released a Christmas album, "The Season." This year, he announced that he would be singing background on Dolly Parton’s new album.

"’Don’t Stop Believin’’ is about getting on the midnight train, and you can go anywhere – everything is possible," Cain reflected. "That’s what we accomplished together. We soared, and we made it work. We did the best that we could. And I’m proud of what we’ve done, all of us."

"Journey: A Voice Lost . . . and Found" premieres June 25 at 9 p.m. on Reelz. The Associated Press contributed to this report.