you could also try adjusting your shifter, its possible that it is slightly out of alignment. this is all done under the console at the shifter itself.
We bought this house in 2020 I was so excited to finally have a 2 car garage. Which has been filled with home improvement projects and garden tools since then.
The ford fluid is fine the heavier weight is what is recommended for gen 1 which has the same transmission. If a plastic piece came out you lost the pad in a shift fork. This will keep that gear from fully engaging you need to take the transmission apart to fix.