In a pickle 70 valiant pitman replacement

So i oerdered a replacemmt off rock auto and evrything seemed to be going on just fine. Then the unexpected happened. The pitman doesnt want to go on all the way up. Its got about an half inch from meeting the bottom of the steering box but the nut doesnt want to turn and i dont want to destroy the nut. What do i do.

Edit: took off the nut and the bottom of the splines have met the top of the washer. Thats why it wont tighten anymore. On a related note. I need a new nut anyone wanna sell me one?

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