Hi Darryl, The Ford axle does not have a seal in the tube, so don't pull your diff.
The inner hub seal has a flange that pokes into a ring mounted by the bolts that mount the brake backing plate. If the inner hub seal leaks, oil is flung / fed into this tin shield and drains out the back of your backing plate, through a ( tell tale) hole at the lowest point. These block up easily and require occasional clearing.
There could be an outer hub seal, but not all carriers have them(parts book)
It is found between the two retaining nuts. The seal in the Australian pattern carriers is a cast ring that is fitted to the outer circumference of the pegged locating washer. The outside fits snug into the turning hub and the locating washer stays static on the axle stub.
This prevents diff oil running / migrating through, and mixing with the wheel bearing grease.
There is a plug in the hub. I think you are supposed to replace the plug with a grease nipple, pump in a bit of grease, and refit the plug. Now days you would pack the bearings on assembly, and forget about them for 5 or 6 years.
IF you carrier does not have the outer seal then basically I would avoid parking my carrier side ways on steep slopes, where diff oil might run through the grease and out through the inner hub seal.
You diff should only be filled to the bottom of the fill hole, which means quite an angle would be required.
I hope that's what you need.