I have a 2006 M6 with 1000 miles on it. At times I've started to notice (within the last 300 miles or so) the shifter seems excessively notchy or sticky. The condition seems to get better after 10-15 minutes of driving but never completely goes away. Then there is the odd time (every 3rd or 4th time I drive the car) where the shifting is very smooth \ low effort. Is this normal? What would cause this fairly significant fluctuation in shifting effort? I have also noticed an occasional clunk (kinda like it's gonna grind but then goes in, giving a little jerky feedback through the shift handle) when going into third. Any thoughts?