In March 2017 a 2 MW turbine at a UK site experienced a gearbox failure. After the replacement, our Drivetrain Integrity Monitor identified an anomaly with the drivetrain temperatures. Further investigation revealed that one of the components on the new gearbox was defective and that this was having a negative impact on performance, with production reduced by approximately 6%. The OEM replaced the component and production returned to normal levels. This preventative action also avoided the risk of a failure, which could have resulted in approximately a week of downtime and GBP 6,000 of lost revenue, which would have had to be claimed against the OEM.