I added a drain plug to the front axle housing.
Located the center of the lowest part of the housing, on the back edge there is a beveled are where the rounded are meats with the flat bottom of the casting. Drilled a hole for the 1/8 npt tap, used the evacuating fluid to flush the drill debris as well as the tap chips. Had some extra synth lube on hand and used that to ensure all chips flushed out. Used a brass 1/8 plug and then filled the diff with amsoil.
The rear diff has proper drain plugs, as does the t-case (both drained and filled with amsoil)