2004 sebring******** when over 2rpm

I have a 2004 sebring. Suddenly the temp light comes on and when this happens you have to slow down below 2 rpm or it surges and shakes badly. My local mechanic has replaced the thermometer, radiator. Now it dosent run hot by the gauge but the temp light comes on and it still doing the badd******** and there is a bad knocking right under the console. Could this be due to a transmission mount breaking?
So far it has cost me 500 dollars and nothing has been fixed.