Just replaced radiator in my 1993 Ford ranger and now the temperature is fluctuating. what can cause this to happen. Also transmission fluid was leaking from radiator

What is your question?

Just changed the radiator today. Put coolant in to see if anything was leaking. Transmission fluid was leaking from radiator top and bottom. So I put piping tape on it.and it stopped leaking. So I cranked it up and the temperature started fluctuating up and down. Even when I was driving to see if it would continue to leak.

What makes this problem better or worse?

When it's idling

How long has your 1993 Ford Ranger had this problem?

Just fixed radiator today