Hard to understand what has happened just from reading your story.
I assume the hollow pin attaching the coupler to steering box was removed and re-installed ?....... and the "lid" has been pulled from the coupler by accident
I drove for MANY years with the "lid" totally loose.... as there is another pin holding parts together (see pic)
.....the lid is for keeping dirt out......
I finally took the coupler apart, re-greased it, and tack welded the "lid" back on.....
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