There are 4 owner-reported powertrain & transmission complaints for the 2015 GMC Sierrain NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
DRIVING NORTH ON THE GARDEN STATE PARKWAY IN THE CENTER LANE IT FELT LIKE I HAD A BACK TIRE BLOWOUT BUT WHAT HAPPENED WAS MY REAR AXLE BROKE CAUSING MY VEHICLE TO BE EXTREMELY HARD TO CONTROL. I WAS TRYING TO STEER THE VEHICLE BUT COULD NOT CONTROL THE TRUCK, IT FELT LIKE I HAD LIMITED BRAKING ABILITY, SMASHING INTO GUARDRAIL IT FINALLY CAME TO A STOP.
VEHICLE RANDOMLY AND REPEATEDLY SHIFTS INTO NEUTRAL FROM DRIVE, WITOUT ANY INPUT FROM DRIVER, DURING NORMAL DRIVING CONDITIONS. VEHICLE RANDOMLY AND REPEATEDLY LOSES ACCELERATOR PEDAL CONTROL AND FUNCTIONALITY DURING NORMAL DRIVING CONDITIONS.
TL* THE CONTACT OWNS A 2015 GMC SIERRA. THE CONTACT STATED THAT WHILE DRIVING AT VARIOUS SPEEDS, THE TRANSMISSION VIBRATED CAUSING A HESITATION WHEN THE GEARS SHIFTED. THE CONTACT MENTIONED THAT THE FAILURE WAS MOST SEVERE WHILE DRIVING AT SPEEDS BETWEEN 40-50 MPH. THE VEHICLE WAS TAKEN TO A DEALER WHO CHANGED THE GEAR RATIO AND ADJUSTED THE REAR END. THE VEHICLE WAS REPAIRED, BUT THE FAILURE RECURRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE FAILURE MILEAGE WAS 250.
2015 GMC SIERRA 6-SPEED AUTOMATIC TRANSMISSION FAILURE @ 1800 MILES. AS I WAS DECELERATING FROM APPROXIMATELY 30 MPH TO MAKE A TURN INTO A ROAD THE TRANSMISSION DOWNSHIFTED AS EXPECTED TO LOW GEAR. AS I ACCELERATED THE TRANSMISSION SHIFTED TO 2ND NORMALLY. AT THIS POINT THE TRANSMISSION SHOULD HAVE SHIFTED INTO 3RD GEAR BUT THE TACHOMETER JUMPED TO 3000RPM BEFORE I REALIZED THAT THE TRANSMISSION HAD SHIFTED INTO WHAT SEEMED LIKE NEUTRAL. THIS LEFT ME BLOCKING TRAFFIC WITH A TRUCK THAT WOULD NOT GO OVER 20 MPH. WHEN I SLOWED SUFFICIENTLY THE TRANSMISSION WOULD PICK UP 2ND GEAR AGAIN. BEING CLOSE TO HOME I WAS ABLE TO LIMP HOME. WHEN I REACHED HOME I PAST MY DRIVEWAY AND WENT TO BACK IN AS I USUALLY DO. THE TRANSMISSION WOULD NOT PICK UP REVERSE! BY THIS TIME A CHECK ENGINE LIGHT CAME ON. I THEN HAD TO DRIVE ABOUT A MILE DOWN THE ROAD TO FIND A PLACE TO MAKE A U TURN SO I COULD PULL IT INTO MY DRIVEWAY. THE TRUCK WAS TOWED TO THE DEALERSHIP WHERE A MECHANIC EXPERIENCED THE SAME PROBLEM ON A TEST DRIVE. (HE HAD TO PUSH THE TRUCK BACKWARDS BY HAND TO BE ABLE TO RETURN TO THE SHOP.) CURRENTLY THE TRANSMISSION HAS BEEN REMOVED FROM MY BRAND NEW TRUCK PENDING INVESTIGATION. IT HAS ONLY TO GEARS 1ST AND 2ND. THIS IS A SERIOUS FAILURE THAT COULD HAVE HAPPENED WHILE MERGING INTO TRAFFIC ON THE INTERSTATE. LUCKILY I WAS ON A BACK ROAD IN THE MIDDLE OF WINTER! *TR
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026