I have an 1988 90 Quattro sedan with 110k miles ,runs pretty well except for a few quirks . After an oil change and complete trans. and diff. fluid change I am getting a grind when I shift somewhat quickly from 2nd to 3rd . Even if I depress the clutch all the way. The fliud level was checked and is okay . Should I go to a heavyier oil for trans. Mike Mueller San Jose, CA