Noticed noise and vibration when in four wheel drive. Chevy dealer inspected and determined that a plastic plug on front differential had failed and drained all of the oil from differential resulting in failure. Chevy has re-designed the faulty part (obviously as a result of many failures). Front differential assembly was replaced. Car was repeatedly returned for service because of no 4X4 function. Eventually, transfer case was removed and inspected only to discover that clutches were completely destroyed from differential failure. Transfer case assembly was replaced. Suburban had 40,000 miles upon initial failure (4,000 out of warranty). Chevy sent owner a check for $600. Reccomend that all Suburban 4X4 owners immediately replace the plastic plug with new design (approx $23 part) or expect failure. Chevy will not accept reponsibility. Old parts are available for inspection.

- Louisville, TN, USA