It is a common problem, our dealer called them all back and replaced gears. We have one built Sept of 97 and supposed to have the problems solved. Check with you dealer. Maybe all were not called back in.
The new gears (AH in place of AN numbers) are a new technolegy. They are much stronger. If Chevy designs a new piston that delivers more hp and lower fuel consumption, should you get it at no costIJ Things change, machines and methods improve.