British claim Van Gaal is on the brink of the sack after a run of six games without victory and he stormed out of his weekly press conference after criticising the speculation about his job.
But despite rumours of discord over his methods within the United dressing room, Rooney says that the players are firmly behind the manager.
“We`re fighting for the manager and trying to get results to turn this around,” Rooney told Sky Sports.
“You have a lot of people talking about things they believe are happening, when in reality the people writing that stuff don`t know anything that`s happening.”
United slipped to fifth in the Premier League last weekend after losing 2-1 at home to promoted Norwich City — their third defeat in succession in all competitions.