That oil is going somewhere, so you definitely have a leak.
Also, when you have a leak, often you leak oil out and water back in. As the drive warms, fluid is pushed out, and as it cools, water is sucked in. (resulting in milky oil as LouC said.). It's possible that the oil does not look milky at the upper gear housing, but the lower gear housing will be milky or worse. Take a sample from the bottom drain and see. Need to get it fixed ASAP.
_________________

"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings