Mira & I would like to thank BJ at RockSolid Performance here in Cedar Springs, Michigan for the project sponsorship via custom machine work on Mira's rear Dana 44 truss. Much appreciated, BJ!
The issue was due to the slight difference of placement of the axle vent fitting on an XJ vs. an LJ. The truss is an XJ truss, while the donor Dana 44 axle was pulled from my 2005 LJ.
Original hole (shown on the opposite side):