So I drive a 2006 MS6 with only 15k miles. I've had this problem for some time and never realized it could be a serious issue. When shifting into second gear (whether downshifting or upshifting), the shift knob bucks and pops out of second gear. However, if I hold the shifter knob in 2nd gear for 1-2 seconds and gently apply the gas after letting out on the clutch, it will not buck out of second. This problem only occurs with 2nd gear and no other gears. I've been told from one dealership that the entire tranny will need replaced and from another dealership that it could be the synchronizer on 2nd gear. Anyone else have this problem or at least know what the true problem is?