There's a TON of posts about this - not that you shouldn't ask, just,
there's lots more to see and read other than this little bit I'm posting
here...
All years driveshafts are functionally equivalent.
Get both a driveshaft and a cup, and also the seal on the shaft at the cup.
The cup will come off and go back on with an air gun. I don't have a clue
as to how you might put it back on at the right torque with an air gun.
There's three degrees of freedom on the cup nut. If you try to loosen it,
the internal gears will just transfer over to the spinning flange gear, getting
you nothing. If you can hold the flange gear, then the whole case will want
to spin, getting you nothing.
When we did it recently at Stanley Steamer's house, I brought over an old
flange, and we drilled holes that matched the fingers on the flange in a
stout piece of plywood. Then we screwed the piece of plywood to Stanley's
deck next to the building. That defeated two degrees of freedom, and we
could both loosen the cup nut and torque it back at the end...


-Mike