As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CRUISE NR1 I.D.G. HAD AN OVERHEAT TEMPERATURE READING OF 189 DEGREES. I.D.G. DISCONNECTED AND AIRCRAFT RETURNED TO BASE. AS A PRECAUTIONARY MEASURE THE I.D.G. HEAT EXCHANGER AND GENERATOR CONTROL UNIT WERE REPLACED ALONG WITH THE I.D.G.