ENGINE LIGHT CAME ON AT 78000 MILES TOOK TO DEALER AND TOLD ME IT WAS TRANSMISSION CODES.WITH 78000 MILES DEALER SAYS I NEED A NEW TRANSMISSION AT $7000.THERE ARE KNOWN PROBLEMS WITH THIS YEAR AND MAKE OF VEHICLE AND NO RECALL.DEALER SAYS THEY REPLACE THESE ALL THE TIME BUT GM WONT DO ANYTHING ABOUT IT WHAT CAN I DO