Cummins Reman Turbo

[eggtrucks]

Im having issue with cummins isx 2250 turbo leaking oil, its bad enough the intake side has oil as well. I replaced turbo TWICE with cummins reman, and checked the things mentioned above, and all seems well, slight positive pressure when disconnect pipe where shown, crankcase filter has the maintenance free version, i blew air through the drain tube, its not clogged. What else could be causing turbo to fail? or could it be another issue and not the turbo? Ive read here its possible to get badly rebuilt reman, i guess i could just be the unlucky one to get 2 in a row, but i want some suggestions on what else to check so i can be certain theres not something else causing it. Thanks for advice!