McClaren joined the station before agreeing to take up his old coaching role as part of Erik ten Hag's backroom team, and also admitted 'five or six' of the current crop 'don't deserve' to wear the shirt.
McClaren was Sir Alex Ferguson's assistant between 1999 and 2001 and will take up a new role at the club ahead of Ten Hag's tenure.
Speaking about United's tribulations, McClaren pointed to the club's acquisition of Cristiano Ronaldo as the bright spark in a wretched season and admitted that the five-time Ballon d'Or winner kept former manager Ole Gunnar Solskjaer in the Old Trafford hot-seat for as long as he did.
"Ronaldo is the man and they've got to find a way somehow as a team to play around him," said McClaren.
"He's not normal, you can't put him with everybody else. He's like Lionel Messi - they're two players that are just out of this world"
Whilst many have viewed Ronaldo's return to United as a counterproductive addition to the squad, new boss Ten Hag has made clear his plans for the 37-year-old forward.
Asked if Ronaldo will be a part of his plans, Ten Hag said: "Of course."
He was then asked what he can expect from Ronaldo, to which he laughed and replied: "Goals."
Manchester United posted their worst points tally in the Premier League this season with a total of 58, leading to a sixth-placed finish.
United registered 12 League defeats and ended the season with a goal difference of zero, finishing a staggering 35 points adrift of eventual champions Man City.
A number of lacklustre displays this term didn't escape McClaren's attentio, as the coach weighed in on how the problems have arisen, whilst admitting that a number of players need to be shipped out this summer.
"Under the surface there are big problems in the dressing room at that football club," McClaren told talkSPORT back in March.
"No one has solved them. Ole was close and must have fought every day to get them running. The thing that stands out for me is that they don't run for each other.
"The solution is simple, they need a manager that the players can trust and they will run and die for.
"You need to get the bad ones out of the dressing room and this is the key to it. Roy Keane was spot on, five or six don't deserve to wear the shirt."
With the short-term answers already at the disposal of United's new managerial team, it remains to be seen if they will act on McClaren's advice as they embark on a long road to redemption.