Vince,did you ever get your downshifting problem solved? If yes,then will you please describe details of repair. Check my posts under Rebenz. I have a 1992 500SEL that has the same symptoms. I was wondering if it had anything to do with the valve that keeps it from upshifting until o2 is warmed up? I have not recieved any reponses on my posts either. I will let you know if i find my problem if you will do the same My downshifting becomes worse as car warms up,does yours? Thanks Bill