One problem I had after exporting Access zip code as text to an Excel file
was being unable to have the Zip Code format go to Excel.

I solved the problem by highlighting the Zip Code fields/Format cells,
selected number, and the diagonal yellow warning sign gave the option of
"number stored as text" or "convert to Number." I chose, "Convert to Number."

Only after converting to "Number" would the data format correctly by
selecting: Format Cells/Special category/Zip + 4