Fred backs "good person" Ole Gunnar Solskjaer but says Manchester United have a "vanity" problem
The Brazilian midfielder has been one of United's standout performers this season, despite United's inconsistencies.
The Red Devils are currently six points adrift of the Champions League qualification spots ahead a of a crunch clash with fourth-placed Chelsea next Monday.
Solskjaer has come in for criticism throughout the campaign, but Fred believes he is still the right man for the job.
However, the former Shakhtar Donetsk man did admit that United have a "vanity" issue inside the dressing room, and has called on his team-mates to be more unified on and off the pitch.
"We need to improve as a group, our group lacks the ‘sticking together mentality’, we have lots of problems," he told De Sola.
“There is always some discussions within the group. [There is] a little vanity, yes, as there is in most groups.
"We must stop this, we should talk less in the dressing room and start running on the pitch. When everyone has the same goal, that's when we'll move forward.
“We need to be on the same page and today some players have different objectives, there are players that just want to solve problems alone and this is wrong.
"[Solskjaer] He's a good person and a good trainer. He is a young manager, and will grow and improve. He will help us."
United will move to within three points of the top four if they win at Stamford Bridge next week, although defeat would be hugely damaging to their Champions League chances.
The Red Devils will face Club Brugge in the last 32 of the Europa League and Derby in the fifth round of the FA Cup, as they seek the first piece of silverware of the Solskjaer era.