2023 GMC Sierra 1500

I had my 6.2 engine replaced at 26,000 miles and the transmission rebuilt. The engine was contaminated with metal shavings and the transmission rebuilt for internal defects. The new engine is running fine but the reliability is a concern after reading about other customers having the same problems. My name is [XXX] . The engine replacement and transmission repair was done at Ed Martin GMC in Carmel Indiana. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While entering the highway from a downward slop exit ramp and towing a trailer, my truck shuddered hard and briefly locked up the rear axle. It immediately went into limp mode with a message that driving speed will be reduced. It also wouldn't shift past 5th gear. When the event took place, the OBD2 generated over 20 trouble codes. My local dealer advised I could drive it to them for repair. Upon dropping it off, they now advise it's NOT safe for driving and they have no eta on the parts to repair the issue. It's now been at the dealer for a week with no update. This is a well known issue that GM refuses to repair or provide a reasonable timeframe for repair. There are countless videos such as this one that show what happens when this takes place. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

With out any warning the truck stop running at stoplight an would not start back up. We could not move the truck out of the road and blocked traffic for almost 1 hour waiting for the tow truck and getting it loaded on the tow truck (truck would not go in to neutral). The truck is now at the Dealer and they are saying that the engine seized up and will need replaced.

purchased a 2023 GMC Denali, 1500 on January 12, 2025. after about a week,Started to hear knocking ticking noises took the truck to the dealership with 20,362 miles . dealership diagnosed that the lifters on the driver side went bad dealership replace driver side bank , picked up my truck drove it a little over 500 miles and still heard knocking ticking noises. Send it back to the dealership and dropped it off dealership told me they would keep me an update on it.Emailed called have absolutely no idea what’s going on with my truck. The dealership did mention of a possible engine replacement. But did not confirm after many attempts. Trying to attempt to contact the dealership emails phone calls still no answer. Called General Motors. They informed me the dealership ordered a new engine for replacement. That definitely worried me and I asked for a vehicle replacement or refund General motors, declined my request. Now I am not so confident in my truck what else could go wrong since the engine is going to be replaced? What about the transmission? Could it affect it? I don’t know> The damage was significant in order for the engine to be replaced you just don’t replace an engine just because, there was no light indications that something was going wrong with my truck. I’m glad I wasn’t driving far when I was hearing these noises coming from the engine because the engine could have seized left me stranded who knows could have crashed if the engine came to abrupt stop because of the engine failure. I purchased this truck January 12, 2025 . The total of time that I have had my truck since January 12 has been 15 days. today is February 6 on Friday, February 7. My truck has been in the shop literally 30 days exactly. Still no update on when it will be ready. This is so frustrating and such a big inconvenience.

Valve Body. While driving the vehicle, hard shifts occurred; the vehicle check engine light came on and stayed on while the vehicle went into limp mode. I was able to link to the GMC dealer. The dealer was not and would not inspect the vehicle at that time. I was told I needed to leave or return in two for inspection. The left vehicle was inspected the next day and determined as a value body. The GMC dealer found the part in another state and has the part shipped. I installed the part, had the GMC dealer search it, and performed a recall update.

Transmission Light has been on & off for a month and half. Had it at dealer twice, dealer will not confirm a problem. Truck shifts and bucks between first and second gear. Makes stopping in traffic difficult as truck will surge and jump when down shifting while stopping. Took truck to AAMCO Transmission shop. Confirmed problem, no new transmission units or rebuild parts are available for the GM 8 Speed transmission. AAMCO is replacing unit with a used one. This is a company truck also have a second truck having the same issues with half the miles of this unit. In my opinion GM is aware of the issue in that with both trucks at dealer with same issue, they just send me off with no documentation so as to not have a paper trail. Also no new units available makes me believe that GM can not keep up with warranty replacements.

Driving truck at highway speed and went to pass a group of slower vehicles on my right. I increased speed to 75 mph and the engine stopped and I had no acceleration. Engine would not shift into Neutral and would not restart. I coasted off to an exit ramp and the truck stopped in the middle of it blocking traffic for about an hour. Highway Patrol was on site to help direct traffic through the intersection of the off ramp and side road. We sat for approximately an hour before a tow truck could get us out of the intersection. The truck transmission was locked tight and the tow truck had to put the back wheel on skates to move it. I had to pay $175.00 to this tow truck company to move me approximately 200 yards to a local restaurant where we waited for the GMC provided tow service to arrive. GMC provided tow truck would only tow to nearest dealership which was in Weimer, TX. At the time of failure there was no warning. The truck just shut down making loud wining noises since the transmission was still in gear. This was an extremely stressful event and I was worried that someone was going to strike us at highway speed from the rear. Traffic was heavy that day on [XXX] heading [XXX] towards San Antonio and most left lane speeds were 75-80 mph and bumper to bumper traffic. The GMC Dealer in Weimer was very professional and inspected the engine on Dec 2nd notifying me that is was a total failure and would need to be replaced under warranty. The dealer had a new engine in hand within a few days and the truck was repaired with two weeks. I had a couple other issues with the OnStar system and the wireless after I picked up the truck and drive it home. I returned it to the dealer and proper parts were ordered to replace a bad control module that had failed during the engine failure. It took some additional time on my own after this was replaced to get my OnStar account back up and running correctly. This truck also had "tailgate drop" issues that the dealer fixed. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMAT

Complete engine failure while driving on interstate. Vehicle went into neutral. After rolling to a stop on highway. Vehicle would not go into gear. Tow was unable to put vehicle into saftey mode and had to drag vehicle onto tow bed. At dealership techs were also unable to get vehicle to turn on or go into gear. Dealer advised the engine was complete seized. This happened while traveling on the highway there was no warning or signs of something being wrong. Vehicle simply lost all power and went into neutral while traveling 70mph with 37k on the odometer.

Valve Body failure. Truck rear wheels lockup during failure as transmission was unable to get past 6 gear, sending truck into limp mode at highway speeds. Codes P0700 & P0747, no issues before failure. Dealership has replaced the Valve Body, but the part number model MQC part# 24065353 has not been redesigned and feel this will be a continuous issues to saftey not knowing when it will fail again.

The trucks engine completely shut down while going approximately 60 MPH while merging onto the highway. The trucks dash flashed multiple times, a ticking noise was heard, it put itself in neutral, and shut the engine off. All power was lost. I did still have brakes. Safety was a concern as there was a vehicle behind me entering the highway too. Cars to my left as well passing at highway speeds. Once I got the vehicle stopped on the shoulder of the highway it put itself in park. It would not restart. The vehicle was towed to a local GMC dealer. There were no warning lights of any kind that came on. No indication that there was a problem. A couple days later I was informed that the truck would need an entire new engine upon inspection. I was also told by the dealer that the truck had no oil at all in it. The engine consumed it internally by their evaluation.