My port engine drive oil pressure was down. (DD 8V-71 Allison Direct Drive)Checked the level and it was on ADD.Oil looked normal at that point.Added about a quart and brought it up to full.After running engine at idle, rechecked oil and now it seems milky and bubbly.What had me looking in the first place was what seemed like drive slip.Engine was operating at normal RPM say 2000 and power from port engine didn't seem to get to the prop.I shut down the Port Engine out of caution. After about 15 minutes, fired it up and everything seemed normal, just a tad lower on the Drive Oil pressure gauge for port.Anyone have any ideas on what is letting Water? Into the drive, if that is the case?Sounds like something expensive.Hoping this is an inexpensive repair, but I’m a realist.