AC/DC perform on stage. Photo / AP
As they made their way around the globe between 2008 and 2010 on the tour that grossed them almost half a billion dollars, Malcolm had days when he couldn't even remember where he was.
"I thought that at times it was not Malcolm with me," Angus admitted.
Malcolm retired from the rock group in September and is now in a special care home in Sydney.
But the band have stayed together and put out their next album - their first without Malcolm on bass - entitled Rock Or Bust.
Despite announcing a national tour for late next year, or even early 2016, the band still don't know the fate of their drummer Phil Rudd, who will face court again in New Zealand, on kill threat charges.
Earlier in the week, Angus and AC/DC frontman Brian Johnson made a guest appearance on Triple M's The Grill Team where they revealed it had not been all smooth sailing within the band in the lead up to Rudd's arrest earlier this month.
Brian Johnson and Angus Young of AC/DC. Photo / Getty Images
"He's in a strange place, in a strange situation," the rocker told hosts Matty Johns, Gus Worland and Mark Geyer of his band mate.
"It's something we have to get resolved, if we're going forward, something has to get resolved," he continued.
Rudd is set to appear Tauranga District Court on November 27, charged with threatening to kill a man and drug-related offences.
The rock legend was initially charged with attempting to procure a murder but those allegations were quickly dropped.
AC/DC's drummer Paul Rudd. Photo / Getty Images
Scottish-born Young said the November 6 arrest of his long-time friend was not the first of the band's issues with the drummer.
"We had a few problems ourselves before he got into this situation. There was a lot of strange behaviour going on. I guess you could put it down to him just not showing up for a lot of what we were doing and when you have to get to a stage where you have to convince someone to be there, you know it wears thin after a while - but it's something we have to resolve."
Young was unable to say if Rudd would join the band when they tour Australia late next year or the beginning of 2016.
"It is a bit of a question mark... we go back a long way, he is a great drummer, but I think over these last few years, I don't know what he's got into or anything - I guess it doesn't help the situation that he's in."
Read more:
• Phil Rudd 'like Hugh Hefner' and 'spent a yearly wage' on women
• Hard rockers beat the hard knocks
On November 6, the rock legend appeared in court on charges of attempting to procure a man to murder two other men between September 25 and 26 and with threatening to kill another man on September 26.
He was also charged with possession of amphetamines and cannabis following a police raid on his North Island home earlier that day.
But Tauranga Crown Solicitor Greg Hollister-Jones said after reviewing the file the next day that he had "made the decision that there was insufficient evidence to proceed with the charge of attempting to procure murder."
Rudd in the High Court in Tauranga this morning. Photo / Alan Gibson
However, he still faces the threatening to kill charge.
The drummer, who released a solo album, Head Job, in August, was released free on bail.
Fans at the global launch of new album Rock or Bust, in a town in New South Wales called The Rock, were told that if they pre-ordered the album they would have a chance of winning tickets to the Australian shows.
A Sony Music representative told the 1,000 people who turned up to hear the 11 songs:
"You will win tickets and flights to your nearest capital city to see AD/DC when they tour Australia, which will be either late next year or in March 2016."
- Daily Mail
