Silverdollar, ya need a service manual.
There are 2 separate "chambers" isolated by shaft seals and the hitch piston seals.
1. The transmission case (SAE 90 gear oil sump).
2. The torque tube case (hydraulic oil sump). The Eagle hitch piston mounted in the top of the aft part of the transmission case is part of the torque tube hydraulic oil circuit. The piston is single acting, oil supply and return are through the same line. Any piston seal leakage is into the transmission case.
Ref to the pix for normal relative full oil levels.
Shaft seal leakage is simply migration to equalize levels. Eagle hitch piston seal leakage is hydraulic pump pressure. So if you're "oozing" out the vent, the piston seals are definitely leaking. Doesn't mean the shaft seals aren't leaking also but you have start somewhere.