This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
Bob Meyer wrote about the Stratus (Cirrus/Breeze)'s automatic transmission
making a buzzing/ratcheting noise when shifting gears or pulling to a stop.
He said this noise, which also occurs on the Acclaim and other cars, is
normal and comes from the solenoids. It is most noticeable from outside the
car. He warned that a continuous buzz or whine could indicate low fluid or
a bad pump, "But if what you're hearing is only during shifting from park
into reverse or drive or coming to a stop, then the dealer is probably
telling you the truth."