I must have misread something in one of your other threads. I was under the impression that you had Yukon gears on the Yukon diff.
That might be it, then. Ford gears should be set to Ford specs.
(Also, since the gears are Ford, your break-in period might be less intensive than the Yukon one. The Yukon gears are said to have a "phosphoric coating" that contaminates the oil, necessitating a fluid change after break-in, unlike Ford's simpler break-in procedure. EDIT: on second thought, the Yukon diff's spider gears probably have that coating on them. So maybe you should proceed with the 500-mile break-in after all.)
1995 Mustang GT (5.0), daily driver
1995 GMC C2500 (5.7), alternate daily driver