Misalignment of the drive belt pulleys can cause a chirping or squeaking noise from the drive belt.Google+
Car Problem Reports
Chrysler Pacifica Drive belt noise due to misalignment of drive belt pulleys
Chrysler Pacifica Problem
Engines Affected: 3.5L V6, 3.8L V6
Average Mileage: 469,666 mi (80,000 mi - 1,222,000 mi)
Visitor, 2004 Chrysler Pacifica, 3.5L V6, 107,000 mi
Rattling noise coming from under hood.Opened the hood followed the sound and the bottom belt pulley rattling and belt moving all over. Problem just found so no answer on how it was fixed.