Hi
The seal wont be on the shaft it will be in the retainer its a tight press fit in there. It also has the bearing behind it as you look from the back of the tractor so it wont come past the bearing if that's tight too, it will depend on how tight the 2 support bearings are in there housings or on the shafts as to what will come out when you take the retainer off.
You could end up with retainer and shaft as one lump, If the rear bearing is the loosest interference fit in it's housing.
You won't know until ya try what way it will come out.
when its apart make sure the bearings don't turn in the housings or on the shafts as they can wear and become loose on both parts. I just had a green colored tractor in the shop for pto work and it had done this. Parts where $5000 Tractor worth $6000 so it got a $1000 in new parts and a pot of bearing fit for $60 which is what the guy wanted to spend

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Yes the hill idea works but a couple of times i tried it i needed more parts and by the time they came in it was raining and it delayed the job longer than having it in a shed and draining the oil, Plus I was working in mud putting it together

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I guess my luck is as good as yours

. Like an old guy said once if it wasn't for bad luck id have no luck a tall some days

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Regards Robert
A Fordson is for life not just for Christmas !.