case 850 torque convertor

hi, i have an old case 850 traxcavator with a couple of issues i'd like to try to sort out. The first is to do with the torque converter which overheats after about an hour of use or shorter if i'm working her hard which then brings the temp of the motor up. A few things I think are related to this is a build up of pressure in the clutch housing which you can see at the clutch housing inspection plate leaking oil, the other is the seal at the bottom of the clutch housing dust plate leaking which then empty's all oil from torque and transmission. The other issue is this seal on th bottom of the clutch housing dust cover. I have tried several times with different gasket materials to get it to seal but as of yet have been unable to get a complete seal. As I said these 2 issues may well be related but that dust inspection plate is a difficult shape and has given me nothing but grief.