I have a 5r55e from a 2000 explorer that I rebuilt and installed in a 1997 ranger when transmission is cold it shifts great but as soon as it reaches normal operating temperature it shifts hard from 1st & 2nd and downshifts hard from 2nd to 1st.Took yellow spring out of intermediate servo and upshift got better but downshifts stayed the same.I have checked codes and corrected those issues with no results anybody have any suggestions.

 

If you haven't tried this yet , give it a try.
Disconnect the coolant temp sensor and you will get a c/e lite, but what we are trying is to prevent it from going into closed loop where the PCM controls some outputs. If it stays working ok then I would suspect there is some conflict between the 2000 PCM and the 1997 PCM.