When you change the oil of the IDG, check the IDG drainplug for cracks. It often happens that the plug is installed with a too high torquevalue, causing it to crack or even break apart. The plug is not that strong and made of aluminum. It might cause a small oil leak making the IDG looking ‘wet’ without finding a clear source of the leak. The torque value is about 65 lbs/inch iaw amm 12-13-21. See pictures of a cracked drainplug. The p/n = MS9954-05