Well, it can be fixed of course. This is just bolting and taking things apart and putting it back together while keeping all the shims strictly labeled and in order. Or maybe none of that is required and that seal can be put in from outside. Wouldn't that be sweet?
All the compact front 4wd axles are very similar now. So chances are good that your whole front axle can be rebuilt with reference to a general 4wd front axle shop manual. Anyway, that is where I would start - with some study of some good manuals.
While you are at it, check if Branson designed their own front axle or are using someone elses.
If you have to unbolt to go inside the axle, the seals are like bearings - they are made to universal sizes and rarely if ever are they proprietary to one brand. For bearings and seals the ID for the part is printed right on the part. So you can buy either online or off the shelf . That goes for a lot of tractor parts, by the way. Except for older days when JD and others used to make their own parts - but those days seem gone now.
Changing to a more viscous multiweight oil such as 70w-85 gear lube in the front axle might slow it down. Adding a cup of oil now and then with a drain pan under is still a solution.
rScotty