I have a 2006 Pontiac Grand Prix GXP with the 5.3L V-8 completely stock. Lately, I have been having an issue with the transmission which seems to be fairly common, but I have yet to find a fix. When the vehicle is started cold, and driving maybe a block or two then stopping at a stop sign or stoplight and then try to take off again, the vehicle seems very hesitant to go, will shudder for a second or two and CLUNK quite harshly into gear about half-way through the intersection. It seems as though it tries to start in too high of a gear??? Vehicle only does it when cold, and no codes have shown up with diagnostics. The vehicle is in the shop right now for this, and also a hesitancy when up-shifting from 2-3 that causes a slight RPM flare. The extended warranty company has sent out an inspector, but the technician at the dealer has been unable to duplicate this problem for him each time he is there. Transmission fluid shows full when running warm in neutral, with no burnt smell or any visible metal. Any help with what may be the issue or anyone with this same problem that has found a fix, I would greatly appreciate it!!! Maybe it is some information I can pass on to the inspector or onto the technician. Dealer is calling out another inspector one more time and will leave the car sit for the entire weekend to make sure it is bone cold when the inspector gets there this time. I will also try to meet the inspector there this time (if possible) to see if I can duplicate the problem for him myself! Thanks!!!![]()