UPDATE ON 10192218 AND 10192426. 2007 GRAND PRIX GXP DEALER ATTEMPTED REPAIR TRANSMISSION. PER GMS TECH SUPPORT, DEALER PULLED TRANSMISSION, REPLACED FINAL DRIVE GEARS , AND BEARINGS. PROBLEM NOT RESOLVED. DEALER THEN REPLACED TRANSMISSION, BUT WITH GM RE-MANUFACTURED"PART. ALSO, DEALER STATED THEY COULD NOT OBTAIN A BRAND NEW TRANSMISSION FOR ANY REPAIR BECAUSE THE FACTORY SAVED NEW TRANSMISSIONS FOR THE PRODUCTION LINE VEHICLES. 15 DAYS AT DEALER. AND WAS TOLD CAR READY FOR PICK-UP. DROVE THE CAR AROUND THE PARKING LOT AND NOTICED GEAR SHIFT DID NOT LOCK INTO PLACE IN ANY GEAR BUT MANUAL. REVERSE, DIDN'T WORK, AND TRANSMISSION SHIFTED ITSELF INTO NEUTRAL GOING DOWN AN INCLINE. BROUGHT VEHICLE IMMEDIATELY BACK TO DEALER, WHO HAD TO REPLACE BOTH FRONT BRIDGESTONE TIRES DUE TO OUT OF ROUND AND IRREGULAR WEAR. LATEST SET OF TIRES WERE ALSO DEFECTIVE, ORDERED TWO NEW BRIDGESTONE'S UNDER WARRANTY. SECOND SET OF REPLACEMENT TIRES DID NOT HELP. DEALER TOLD ME THERE WAS NOTHING WRONG WITH THE REPLACEMENT TRANSMISSION, DESPITE DRIVE LINE SHUDDERING. DEALER STATED OPERATED AS DESIGNED. *AK