Questions were raised over the former United manager's continued involvement at the club during David Moyes's unsuccessful spell in charge.
But the current Netherlands coach is sure he will not face the same problems, claiming he is his own biggest critic.
“I don’t think he (Ferguson) is the biggest problem,” Van Gaal said. “I put more pressure on myself than others do.
“I’ll undoubtedly have a drink with Ferguson. We’ve done that before and we like each other.
“But nobody can put more pressure on myself than I do, so I do not expect any problem with Ferguson.”
The Dutchman also insisted he will be in charge of identifying transfer targets this summer, but will not play a role in negotiations to sign players.
Van Gaal added: “I say which players I want and which players can leave. But they (United) have to negotiate. I’ve never interfered with transfers.”
Van Gaal has been viewed by many as a short-term appointment by United, but the 62-year-old believes he can manage into his 70s, though he will leave all transfer negotiations to chief executive Ed Woodward.
“In three years I’ll be 65,” he added. “How old was Bobby Robson? In his 70s.
"[Giovanni] Trapattoni is still active, but I can’t see myself like that.”