Hank,there is an updated alternator belt tensioner that goes alone with an updated alternator that falls under a TS bulletin.
The bulletin addresses 97-2000 w/auto trans.
These parts were put into production on the 2001 w/auto trans.Looks like you are out of warranty,so maybe go with just the updated tensioner.The alternator has a clutch built into the pulley which corrects belt rumble
on the 97-2000,in case you were interested.
Also,when you have the belts off,spin the idler pulleys to check for abnormal bearing noise.I have replaced many a/c idler pulleys for squeeking during a/c engagement.
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MattWalsh - 25 Jan 2002