The contact owns a 2017 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, there was an abnormal sound coming from underneath the vehicle, after which the vehicle lost motive power. The contact was able to continue driving to the destination. The check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the torque converter. The vehicle was repaired; however, the failure reoccurred 2-months later. The manufacturer was not notified of the failure. The failure mileage was 76,000.

- Loda, IL, USA

8 speed transmission shudder reported by GMC for my model. My truck has 35,500 miles and has the shudder posted in a technical service bulletin by GM. The supposed fix is x 20 quart fluid flush, new filter, and flash the computer. GM will not cover under any warranty as they say this is a -??fluid change-?? even though the manual says this fluid should not be changed until 72,000 miles. The dealerships act like they are just hearing about this which is a total lie. They were told over a year ago if they had any new on lot to change the transmission fluid to mobile one synthetic before selling them. This should be a recall as GM knew this was an issue during manufacture. This is a $1200 repair that should be covered by GM.

- Hernando, MS, USA

#1 While merging onto the highway, the vehicle began to shake violently and have a sudden lose of power due to a misfire on cylinder 6 and 4. I was unable to merge onto the highway as the vehicle would not accelerate almost causing me to be hit from behind. I was able to get the vehicle off to the shoulder to avoid an accident as it was barely able to stay running and the CEL was flashing. The failed parts (AFM lifters/push rods and VLOM) have been removed from the engine and saved for review. #2 My family's safety was put at risk as the vehicle had a sudden lose of acceleration while trying to merge on the highway almost causing us to be hit from behind. #3 I spoke with my local GMC dealer and explained the situation and diagnosis that I have completed on the vehicle. That wanted me to pay out of pocket to tow the vehicle in and would not cover anything as the vehicle is barley out of powertrain warranty (72695 miles). I have been an engineer in the automotive industry for almost 10 years and can properly diagnose a vehicle and the issue it has. Trouble codes were provided along with pictures and videos as evidence. I understand when something is a safety issue and needs to be addressed as this is a common issue with GM 5.3l and 6.2l engines. I then spoke to GM corporate (Mandy, case# 9-12424996557) and once again they wanted me to pay for everything out of pocket even though this is clearly a safety concern with their product and the diagnosis had already been completed. This vehicle has all the maintenance records since it rolled off the showroom floor, proving that the failure is not related to neglect or poor maintenance of the vehicle. There is very clearly a design issue or manufacturing issue on this components. #4 Components are available for inspection by mfg. #5 There were not warning lights or any other indicators prior to the failure. Oil pressure was at 40PSI and engine temp was ~200F. All within the normal operating windows of the vehicle.

- Belmont , OH, USA

Experienced hard shifting in my transmission a couple before it all of the sudden it made a thing noise and didn-??t want to move forward to easy. Babied it home and by then it was whining and whistling all the time. I Quit driving it immediately and had it towed. Being only a 2017 I can-??t believe this happened. Plus I had a 2014 prior to this and I had the same issue but traded it off before it went all the way out. After going to social media I am finding out that so many people with mid to late model 2000s have had this same issue, even family. Plus I was told by 2 different transmission places this is very common in these with Chevy and GMC model trucks. How could this be going on? I am assuming because people don-??t know to report. Being on disability and a fixed income this took a hit to my bank account, actually a home equity loan.

- Finger, TN, USA

The vehicle would shudder when trying to accelerate. I almost was hit by a semi truck trying to merge onto the freeway. Made an appointment with the mechanic then a couple days later I was at a stop sign and the vehicle would not accelerate at all. I placed in park the tried shifting back into drive and still nothing. I had to turn the vehicle on and off twice before I was able to shift it in drive an it actully would accelerate. Even then it would shudder and not accelerate fully. Very dangerous. Just hit 100k miles. GMC Certified Mechanic said the transmission is shot and needs to be replaced. Cost to replace over $6,000 Bought the truck in 2020 for $35,500 and just paid it off.

- Redding, CA, USA

Transmission shifting hard. Shuddering around 60-65 mph

- Hampton, AR, USA

I purchased the vehicle in November or December 2022. Since then I-??ve had problems with my transmission. The torque converter was replaced 2 times, it-??s been in the shop 5-6 times and nothing fixed under the warranty when I purchased it. Finally the dealer I purchased from said they won-??t take the vehicle back and won-??t spend any more money on fixing the truck. Now it has become on my dime to figure it out since I gave up trying to have a shop diagnose and fix it. The last shop said I would have to pay to have the transmission removed and possibly have the valve body replaced since the dealer I purchased it from gave the second shop one chance to get it right. The transmission downshifts hard and clunks since the first day of purchase. Makes a weird wining noise still til this day. I have spoken with the owners of the dealership and they did not seem to care about my problem.

- Hamden, CT, USA

Truck has always shifted rough, now with only has 102,000 miles has been serviced regularly exclusively at the dealership. It started slipping gears and I was just informed by the dealer that the torque converter detonated and the entire transmission must be replaced.

- Mount Olive , IL, USA

The transmission is shuddering, hard shifting, shuddering and lunging into gear. It is the 6L80 transmission Also has little to no power, took it to the dealership for diagnosis and they say the transmission is bad, torque converter is also bad sending metal throughout the rest of the transmission.

- Reeds Spring , MO, USA

Transmission temperature sensor has failed. It is available for internal inspection within the transmission pan. Safety has not been in issue, but, apparently it can cause hard shifting when the sensor starts to go bad. You can also easily tell when the sensor is going bad by watching your trans fluid temp needle. It will erratically bounce up and down, sometimes slightly and other times it's big jumps, so you will not be able to tell if the transmission is overheating or running at normal operating temperature. The problem has been confirmed by a local service center. The vehicle/component has not been inspected. There has not been any problems prior to this issue. The check engine light came on 1/24/24 in the evening time. Check engine codes are P0711 & P0700. This is a known issue between 2015-2018 GM vehicle equipped with the 6.2L & 8-speed transmission. There is/was a special warranty number, #N192291660, that qualifies with the 2016 models.

- Saint Augustine, FL, USA

I was driving my truck home from work, when all the sudden the car at a stop sign lurch forward, with the brake applied and was not moving, or I would have hit the car in front of me. Upon, the green light, truck started to shift and go faster, while making a whining noise, at only 26 miles per hour, then, the vehicle, tried to speed up with nothing engaging, and came to a complete stop very aggressively and abruptly, while in traffic, I almost was hit from the sudden stop. Getting to the side of the road, the truck wouldn-??t move anymore, and except in rear gear. Called OnStar service and vehicle was towed to the closest GM dealership, about a mile from my house. This was on a Saturday evening, On Monday, the dealer service agent called me, had already diagnosed the problem as a failed 6L80 GM transmission, this was at 930am, asked if I wanted it repaired I said yes. The dealer called back at 3pm that same day and said the transmission had already been repaired. Which to me is a bit surprising as it needed a new transmission, which should take longer. Glad it was fixed so fast. The cost was to be around 6700 dollars. From my knowledge this is a known issue with these transmissions. My concern, is that I could have been in an accident from a known defect in manufacturing that GM knew about and did nothing to address.

- Butler, PA, USA

Transmission has stalled many times from shifting through 1st and 2nd gear going across divided highways and nearly causing accidents, also it has a very bad shudder and hard shifting.

- Cocoa , FL, USA

My transmission started to shutter then went in and out of gear till it doesn't stay in gear

- Gansevoort , NY, USA

The transmission needed to be replaced car would not go in reverse or foreward at all. It only has 120,000 miles on it.

- Memphis, TN, USA

My 2017 GMC Sierra 1500 Denali started shaking violently and the rpm gage began bouncing 1/4 to 1/2 inch in a very short amount of time. I ran a maintenance facility in Europe with 317 local national and 25 U.S. employees. Two of my brother-in-laws, and one of my nephews are mechanics. Two run their own auto repair facilities. All three reported having to replace torque converters on multiple gmc/chevrolet 1500 trucks. Many at somewhere between 40 and 60 thousand miles. If this is such a systematic problem, and from the number of vehicles they have had to repair it is, why hasn't a recall been issued. Second, in most cases dealerships first charge excessively for replacing the transmission fluid (approximately $900) and then end up replacing the torque converter. The owner has to pay for the transfluid replacement out of pocket because it is considered maintenance instead of replacing the torque converter at company expense...especially if you purchased and extended warranty through a third party. If this is recalled, owners should be reimbursed if they had to pay for it themselves and they should be required to replace the transmission fluid filter as a part of the repair,

- Murfreesboro, TN, USA

After 80K miles on a 2017 GMC Sierra - my 6 Speed AT Transmission HMD 6L-80 failed. There appears to be know flaws in the GMC transmission, but no recall for my model and year.

- Aptos, CA, USA

The contact-??s husband owns a 2017 GMC Sierra 1500. The contact stated that while her husband was driving at approximately 55 MPH, the vehicle hesitated and stalled. The check engine warning light was illuminated. The contact-??s husband was able to restart the vehicle. The vehicle was taken to the dealer where it was diagnosed that the transmission had failed and needed to be replaced. The vehicle was repaired; however, approximately 1 year later the failure recurred. The contact stated that while her husband was driving approximately 55 MPH, the vehicle hesitated and stalled. An unknown warning light and the check engine warning light illuminated. The vehicle was towed to the dealer where it was diagnosed that the transmission had failed and needed to be replaced. The vehicle was repaired; however, the failure recurred. The contact stated that while driving approximately 45 MPH, the vehicle hesitated and stalled. The vehicle was restarted but the vehicle decelerated while the accelerator pedal was depressed. Additionally, the contact stated that she was informed by the dealer that the vehicle failed to shift into the intended gear and as a result, the transmission failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 100,000.

- Shenandoah Junction, WV, USA

Truck all a sudden developed a Lifter noise under the hood and the check engine light came on Friday, September 8th. I checked the oil and oil pressure which was ok. Saturday morning 9/9 I notice some loss of power pulling out on Highway. I took the truck immediately to a friend who is a retired GM Master Mechanic. He coded P0300 and P0306 with 158 miss fires. The following Monday on September 11th I took the truck to Clift GMC in Adrian, MI. They confirmed a Lifter failure and bent Push Rod on Cylinder six. on my 5.3L engine. Since I have learned the AFM System on these engines is driving Lifter Failures. I was lucky my Camshaft was not harmed. My truck had 84,945 miles on it and is six years old. GM offered no, zero assistance. The Dealer could only state this is a well known issue which they see frequently offer a extended Power Train Warranty at a cost of $1600 t $2000 dollars. How is a Extended Warranty a solution to a poor Engine Design? Help!

- Brooklyn, MI, USA

Transmission issues! Very hard shifting! Feels like someone ran into me from behind. Shutters while crushing at 45-48 mph. Vehicle shakes from transmission issues!! GMC will not do anything about it!

- Bush, LA, USA

Transmission slipping in and out of gear. Transmission was serviced 5,000 miles previous to this for the 100,000 mile service at 95,000 miles. No issues were found at the time of service, now truck will slip out of gear on highways without warning. Transmission fluid is not dirty or burnt. Common reported issue according to online discussions and GMC needs to recall this model transmission

- Mount Lookout, WV, USA