Galliani spoke to Real president Florentino Perez about a return to the San Siro for the player in the US, but both parties seek different outcomes. Milan want a loan deal with Real pushing for a sale.
The Brazilian attacker's reported wages of €10m-a-year are also proving to be problematic.
Speaking after Real's 5-1 win over Milan in a pre-season game,
Galliani said: "The operation for Kaka is objectively very, very difficult.
“It is almost impossible. Costs are high, salaries are very high.”
Real coach Jose Mourinho admits it up to Kaka where he wants to go.
“I’m happy if Kaka stays and am happy if he wants to go. In football it is important that players play where they want to.
“He is better prepared to compete at the highest levels. If he wants to stay then perfect. If he leaves then perfect, but we do not want to give him away for free.
“If [Milan] want him, they will have to pay for him.”