8 3/4 leaking diff fluid into Brakes

The inner axle seal (in the housing) is the only one that is designed to keep the gearoil inside the housing and not mix with and wash away the grease in the bearings.
If the bearings are adjusted too loose then the axles are riding 'higher' in the housing, causing the inner seal to become less efficient at the lower part and possibly leak oil onto the bearing(s).
Tightening up the axle-play could solve the issue.