When the members of AC/DC titled their new album 'Rock or Bust,' they meant it.

Already forging ahead without co-founding rhythm guitarist Malcolm Young, whose health issues forced his retirement from the lineup, the band is now faced with the prospect of finding a replacement for drummer Phil Rudd. Up against a shocking array of criminal allegations and accused of erratic behavior (or worse), Rudd has left the group in a lurch at an inopportune moment -- but guitarist Angus Young insists his absence won't change their plans at all.

"We were resolved for us to go forward and I think Phil's got -- it's something he's got to do himself," Young told Billboard. "He's got to sort himself out, I think. But we were resolved to go forward. So at this point it's kind of a question mark. But if we're touring, there will be a drummer in place, put it that way."

And as for whether anyone in the group has reached out to Rudd, who was with the band from 1975-83, rejoined in 1994, and has been behind the kit ever since? "We haven't had contact," Young admitted. "But he has his people that represent him. He's got himself in a pickle."

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