joe -

you saw my reply about essentially the same problem on the tech
threads- my 1/2 shaft wasn't stuck to the diff as your rh side is but still had to be pounded out ie. bang the heck out of it to the right side from the inboard cv joint. In any case i went with 2 replacement rebuilt 1/2 shafts as both sides had damaged splines and lots of scoring on the ends.
likely if the rh 1/2 shaft is totally seized into to the old diff you will not be able/want to use it again- would suggest use it for the core price on a re-built one!

let us know how it turns out - good luck!

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1984 300D Turbo - 231k....totalled 11/30/07 RIP