W221 S550 I think transmission problem
I had a chance to hook up STAR and the fault code was "0720, Mechanical Failure of component Drive Train"
The supplementary info said possible causes of fault could be Transmission output speed.
I was able to shift into D, R, N and P without and issue. I could hear it shift and see it on the dashboard and in STAR. While in D, I was able to manually paddle shift through the gears and hear them shift in 1st and 2nd but not 3-7. I think that is by default so you dont start in 3rd gear or higher. Is there any chance this is something other than the tranny itself? something connecting the engine to the tranny? I dont think this is a sensor as I could hear something mechanically wrong when it first happened.








