Got a 2006 grand prix base 137800mi and I'm noticing when the trans gets to about 174* but gets worse around 200-205* it starts this shuttering on occasion when I start from a stop it will hesitate a second then shutter and slam into first then shifts fine through the rest of the gears. Also noticed that after stopping a few seconds later it will shutter occasionally and rpms go and down I thinks its changing gears but I'm stopped? Would a trans fluid change help any or is it just the worst case scenario that the trans will need to be rebuilt?
