I only recommend Ford Seals Here-(check fitment guide)
The only fluid the differential should be refilled with-(3-4qts required)
Friction modifier-(1 bottle per needed)
This is the differential sealant I recommend-
This is the best Brake Cleaner to get all the residue off-
In this video I show how to replace an axle seal on a 2012 Ford F150 but the procedure is almost exactly the same on any Ford rear end since the 80’s.