Hello all member. I need help about Cummins ISX Turbo

[Dcolumbia]

I have a question on the turbo oil consumption. I had a turbo leaking oil on the exhaust side bad enough that it eventually would not allow the VG piston to move properly. I tore it apart and don't really see a seal there. Had to take the turbo I put on off to replace the exhaust manifold gasket and find that I am still having a small amount of oil on the exhaust side. I will check the drain tube tomorrow but also read that the turbo uses some amount of exhaust back pressure to help prevent leaking at the exhaust side. Question is that since I have very limited back pressure could this be part of my problem. The engine doesn't seem to go through any more oil than usual, about a gallon in 10,000 miles so not sure if this is much of a concern and since it never does a regen anymore the oil is more noticeable in the exhaust pipe than it used to be. Anyone having this problem or had this problem in the past?