What was found
IN FLIGHT, SOURCE OFF, GEN OFF BUS AND DRIVE LIGHT CAME ON SIMULTANEOUSLY, AT FL 350. CREW EXECUTED CHECKLIST, SOURCE OFF, 6.9 AND DRIVE, 6.3. WIRED GENERATOR DRIVE DISCONNECT SWITCH WAS BROKEN TO HOLD SWITCH IN, DISCONNECT, POSITION IAW 6.3. APU WAS STARTED AND PUT ON THE BUS. CONTINUED TO DESTINATION IAW MAINTENANCE, DISPATCH, CREW. ACFT GROUNDED. R & R RT IDG, IDG OIL COOLER, IDG AIR/OIL COOLER, REF AMM 24-11-11, 73-11-06, & 24-11-21. OPS & LEAK CHECKED GOOD.