Hey everyone. Just signed up for this site and think its great. I have a 99 600 f4 with 30,000 miles on it. I just changed the oil to a full synthetic and around 9 to 10 RPMs, it downshifts into Neutral. Could this be an issue with the synthetic? Has anyone else had this problem? I do plan on changing it this week to see if that solves the problem.
Thanks.

 

what synthetic are you using?