The FSM calls for 80wt GL-4 in the transmission & transfer case.
Differentials are 80-90wt GL-5 for open, & Trac-Loks want 80-90wt GL-5 LIMITED SLIP.
Personally, I would NOT use a GL-5 oil where GL-5 oil is called out. GL-5 has a higher sulphur content which will attack brass components. A differential has no brass parts, so the GL-5 is useful.
The oil weight is probably fine. Worry about the additives.
Be kind. If for no other reason, it will confuse the daylights out of people and make them wonder what you're up to. And ALWAYS drink upstream of the herd!