2012 GMC SIERRA 1500 Power Train Problems

The contact owns a 2012 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the transmission unexpectedly downshifted, especially between second and third gears. The check engine warning light was intermittently illuminated. In addition, the contact stated that the engine felt as though the engine mounts were inoperable. The contact pulled over to the side of the road and turned off the vehicle. The vehicle was restarted, and the vehicle resumed normal driving. The vehicle was taken to the dealer; however, no cause for the failure was found. The vehicle was not repaired. The contact stated that the failure persisted. The manufacturer was made aware of the failure, but no assistance was offered. The failure mileage was approximately 20,000.

TRANSMISSION SURGES WHEN GAS PEDAL IS PUSHED HARD AS IN TRYING TO ENGAGE KICKDOWN OR "PASSING GEAR". SPEED IS NOT A FACTOR, IT HAPPENS AT LOW SPEED AND HIGHER SPEEDS. DEPENDING ON SPEED, TRUCK JERKS SUDDENLY AND ALMOST STALLS OUT. SOMETIMES REAR TIRES CHIRP.SEEMS SIMILAR TO THE 8 SPEED TRANSMISSION PROBLEMS LATER YEARS HAVE EXPERIENCED.

WHEN VEHICLE STARTS MOVING FOREWARD FROM A DEAD STOP AND WHEN AUTOMATIC TRANSMISSION SHIFTS FROM 1ST GEAR TO SECOND GEAR THERE IS A HARD CLUNK.THIS HAS BEEN HAPPENING SINCE 15000 MILES.WHEN I BRING TO DEALER ,THEY WANT TO KEEP TRUCK ,LEAVING ME WITHOUT VEHICLE.WIFE AND I WERE ON MAJOR HWY AND HAD TO SHUT VEHICLE DOWN IN TRAFFIC TO STOP THE CLUNK.VERY DANGEROUS SITUATION.

ON 26MAR2017 I NOTICED A TICKING NOISE COMING FROM MY VEHICLE. I TOOK IT TO THE DEALERSHIP 27MAR2017 AND WAS TOLD THAT I NEEDED A NEW FLYWHEEL. I WANTED A SECOND OPINION BECAUSE I HAVE NEVER HEARD OF A FLYWHEEL GOING BAD IN MY LIFE. AFTER SPEAKING WITH A FEW MECHANICS WE ALL AGREED THAT IT WAS NOT THE FLYWHEEL. ON 4APR I TOOK MY VEHICLE TO ANOTHER DEALER WHO CONFIRMED THAT THE TICKING WAS THE FLYWHEEL. THE FLYWHEEL HAD TO HAVE BEEN DEFECTIVE AT TIME OF MANUFACTURING. IT JUST CRACKED FOR NO GOOD REASON OTHER THAN IT WAS POORLY MADE. 2012 GMC SIERRA 1500 FLYWHEEL JUST CRACKED OUT OF NOWHERE ENDANGERING THE LIVES OF AN ENTIRE FAMILY AND WHO KNOWS WHO ELSE IF IT HAD SHATTERED.THE VEHICLE WAS TICKING AFTER A MORNING START WHILE SITTING IDLE.

TL* THE CONTACT OWNS A 2012 GMC SIERRA 1500. WHILE DRIVING APPROXIMATELY 50 MPH, THE VEHICLE HESITATED. THE CONTACT DROVE THE VEHICLE TO THE DEALER THINKING THAT IT NEEDED A TUNE UP. THE DEALER DIAGNOSED THAT THE CAMSHAFT AND UPLIFTERS NEEDED REPLACEMENT. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 140,000. .....UPDATED 08/11/16 *BF THE CONSUMER ALSO STATED THERE WAS AN ISSUE WITH TRANSMISSION. UPDATED 08/17/16 *JB