My problem started by my battery going dead and throwing codes when my wife was driving our M6 to Arizona from Colorado. We took the car to our repair shop that deals with imports and they installed a new battery from NAPA and cleared the codes....mistake number one. It worked for a day and then literally shut down on the highway to which I towed it home. I charged the battery and drove it to the repair shop to now exchange for a BMW battery and cleared codes. By now the car was clunking into gear and throwing codes. At this point I took it to a BMW dealership for them to completely reprogram the car. Now it was apparent that the clutch was slipping and still clunking into gear. They gave me a referral to a BMW transmission shop. Upon receipt they thought we might have a mechanical issue and recommended that we look at the clutch. We found a broken throw out bearing and also replaced the clutch. Now the car doesn't stutter when I start in first gear and is smoother than ever shifting up and down through all gears than ever....with the exception of shifting down from second gear to first while rolling. If I don't shift down and let it shift on its own at full or close to full stop it is fine. It grinds when I shift it down. I'm told this must be a transmission problem...any ideas? It is close to perfect.