As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT GENERATOR DRIVE DISCREPANCY, RETURNED TO FIELD. LEFT ENGINE FUEL-OIL HEAT EXCHANGER REMOVED PER MM THRU PAGE 410 PARA 8. INSTALLED LT FUEL-OIL HEAT EXCHANGER PER MM. CHECKED DPI AND FILTER FOUND DPI NOT EXTENDED OR CONTAMINATION IN FILTER OR OIL. INSTALLED NEW FILTER. LT GEN DRIVE EICAS LT GEN DISCONNECTED PER QRH. REPLACED IDG, OPS CHECKED OK.