The national coach of the Netherlands was confirmed as United's new manager on Monday, having been strongly linked with the role for a number of weeks.
Ferguson brought an end to his hugely successful Old Trafford reign at the end of the 2012-13 season and played a part in choosing his successor, David Moyes.
However, the former Everton boss struggled in his new position, parting company with United in April after just 10 months in charge.
Ferguson has remained a visible presence at the club in his new role as a director.
However, Van Gaal, who will begin work with United after the FIFA World Cup, insists that will not cause any problems for him.
"I will definitely have a dram (drink) with him soon," he told Dutch television station RTL.
"We have done that several times before.
"We can really cope with each other. I don't think he is the biggest problem for this job, because I am always putting more pressure on me than anyone else."
