XDP Xpressor OER Series New RHG6 Replacement Turbocharger XD557Replace the worn turbo in your 2001 2004 GM 6. 6L Duramax LB7 with an XDP Xpressor OER Series New RHG6 Replacement Turbocharger XD557. Issues such as lack of lubrication, oil contamination, worn seals, and excessive temperatures can gradually do damage to the turbo in your Chevy GMC truck. Common symptoms of RHG6 turbocharger failure can include a loss of power, decrease in fuel economy, increased oil consumption, excessive smoke, noisy operation, or