1992 Buick Park avenue w/ 3.8 s.c. Knock from front of engine-I can't see cracked rubber but I can move pulley noticeably on hub.Customer says balancer was replaced before.Aftermarket shows '92[oem 88960259]only,'93 & later use GM # 88960265 Can't find tsb's but remember reading somewhere there were issues with early balancers and an updated replacement is available.GM partsdude knows nothing about that.Anyone know about better replacements available?