please don't continue to drive it with the alt whining like that
the '98 to '02 V6s use a GM sourced (delphi) alternator, a mistake.
One of the diodes has popped inside, which causes charging current to feed back into the alternator itself. Start the car from stone cold and feel how hot the alt will get in a matter of seconds.

Have seen several near fires from this on GM cars, and you don't want that to happen with yours.