You need a pickle fork ... a special tool made for separating the two.
Most of the chain-type parts stores ( Auto Zone/ Advance / O'Reilys ) have a tools loaner program and they have this tool in that program ( usually )
They are not that expensive to buy ( I have a old Snap-On one that I got a a yard sale 20/25 years ago for 5 dollars. If you were close ... I would let you borrow it