8 speed transmission is dangerous. Under light throttle, the vehicle will make a loud popping noise and lurch forwrward. Like stopping at a stop light, driving through a drive-thru. My truck will shake violentlly.. dealer says its the transmission. When I try to enter my garage the truck will sort of jump forward. Delear says its torque converter sutter. Transmission has been worked on 3 time. It seems to get worse. Delears says the 8 speed transmission has many issues but GM does not have a fix. These 8 speed transmissions will end up killing folk.. this stuff happens on a daily basis

- High Point, NC, USA

My truck shifts very hard between gears, especially 1st to 2nd. Feels like getting rear ended sometimes. It also hesitates daily when backing out of my driveway and putting it from reverse to drive. You don't know when it will actually engage making it dangerous when pulling out into the street. Its definitely an issue with the transmission but no fixes offered from dealer yet.

- Morton, IL, USA

"have taken my 2017 GMC Sierra into the dealership twice for transmission issues, the last time was a month ago. Both times I was told that there wasn't anything wrong but that the transmission software was 're-flashed' and that the transmission would have to 're-learn my driving habits'. my truck is still having problems. While upshifting from 1st to 2nd gear, the transmission sometimes hesitates before it engages and then causes the truck to lunge forward with a huge slam. While downshifting from 2nd to 1st gear, the transmission will make a very noticeable 'clunk'. I'm about to take it back a 3rd time. This is extremely frustrating my bought my truck less than 2 years ago and it only has 25,000 miles."

- Bossier City, LA, USA

Transmission shift from 1st gear. There is a problem in the gear shift from 1st to 2nd it slams the transmission when you stop and start. There is a heater in the transmission that puts extra degradation on the oil causing it to need replacement very early. Dealer knows of the issue but has no fix for it only stated they noted the file in case it fails. Unaccepatable for a 55,000. Please look into this.

- Danville, CA, USA

Vehicle was parked on icy driveway (5 degree angle). In park. Vehicle was found at the bottom of driveway against a tree. The wheels were turning and not skidding as proven by treads in the snow. I believe one of the rear tires may have slipped and somehow the opposite disengaged and allowed it to continue backwards. This happened with my 2002 GMC Sierra. The explanation I was given is the differential senses a slip and the other side engages allowing it to turn but if there is a slope the vehicle weight allows it to keep rolling down hill. If someone is behind the vehicle they could be injured or pinned between another object. You can park one on an icy drive and nudge it and it will begin rolling backwards. There should be a pronounced warning of this or an engineering solution

- Hampden, ME, USA

I had the rotors replaced on my new truck at 6000 miles and paid for repairs out of pocket. I continued to hear brake noise. On my way to the dealership on the weekend I was scheduled to have the brake noise investigated and to have an oil change done, I had catastrophic brake failure. A vehicle in front of me made a lane change into my lane and then slammed on the brakes in front of my vehicle at a green light coming to a complete stop from 40 mph to 0 in the middle of the intersection. A car had pulled out in front of him changing lanes from the left lane to right. I mashed the brake pedal to stop immediately and my brakes went soft and to the floor on the second push. When I wasn't stopping. I slammed my emergency brake with my left foot and injured a few toes on my left foot trying to stop before my vehicle. My vehicle did not come to a complete stop. Instead, my vehicle skidded and lightly tapped the vehicle in front of me doing minor bumper damage to both of our vehicles. However there was a Toyota truck behind me, and struck my vehicle directly while I was at a stand still, while the driver was doing over 70 mph when he collided with my Sierra. My Sierra has the pin or part of the caliper that moves the brake pads, completely pushed the piston into the rotor. The vehicle has had brake issues since I paid to have the brakes and rotors replaced at 6000 miles. I have records of the incident and the brake failure from a mechanic and auto body shop documenting the complete failure of the brakes. Directly after the brakes were replaced within another 8000 miles the brake booster on the vehicle went bad and was replaced as well.

- Auburn, CA, USA

I have had several instances where you push the accelerator and you start to go and then it just stops moving like the transmission has disengaged. Started to turn into oncoming traffic this morning and had to stop as as it did this and I was going to get hit!!! it does it a lot, first time I would have been hit!!! GM says they know it's a problem, at shop now again for it! going to get someone killed!!!!

- Cheyenne, WY, USA

1. the transmission shifts extremely rough from 1st to 2nd gear in parking lots at a slow speed and on normal highway or street driving and experiences the same thing while slowing down to stop 2. the engine has recently been having a awkward shake to it while in ideal after it has been running and warm 3. while backing up and turning the wheel, the front suspension will let out a loud clunk sound and the sound will return when turning the wheels back forward after putting it into drive.

- Modesto, CA, USA

Towing a 5900# rv trailer within the specified 7600# tow weight capacity, caused the transmission to overheat and free spin within 10 miles of travel. Transmission overheating occurred when towing (285+), when not towing but in tow mode (264), & when driving (241). Dealer and GMC tech's do not have a correction for the transmission operating above range. V6 engine w 6 speed automatic transmission. Traveling at 60mph. Weather temperature low 80's. leaving the owner in the road with their rv waiting for 20 minutes for the transmission to cool down so it can be moved off the road, is not safe.

- Josephine, TX, USA

I bought this truck used with 12,918 miles on it, April 2018. When driving(especially on highway), and changing speeds, transmission clunks and lurches-automatic transmission. It sounds and feels as if drive train will fall out. I have taken it to dealer twice. The first time, they kept it for 3 days, the second time, for one. The mechanic is able to replicate the noise/lurching, but they are unable to find a cause or correction. They tell me it is not dangerous, but I am concerned that the noise/movement, could cause myself or another family member to swerve or brake hard and cause an accident. The mechanic has tried "updating the software" but that did not fix it. Several other GMC Sierra owners tell me they have had same problem.

- Germantown, MD, USA

When driving at slow parking lot speeds or when coming to a complete stop the vehicle intermittently lunges, surges or jolts, causing the vehicle to move forward or backwards unanticipated. Sometimes the jolt feels like another vehicle has hit this vehicle from the rear, again causing it to lunge forward.

- Dayton, OH, USA

Unintended acceleration when slowing down to come to a stop the vehicle will occasionally engage a lower gear very suddenly and lurch forward. The resulting force is enough to overpower the braking effort being provided by the driver and the vehicle will move forward several feet before the driver can react and apply more braking force to stop the vehicle. The issue occurs randomly and infrequently at very slow speeds (5-10mph). There have been several occasions where ive been braking to stop at a stop light and been forced into the middle of an intersection. Im concerned the issue could cause the vehicle to strike the car in front of it or a pedestrian crossing in front of the vehicle as it stops for a crosswalk. Multiple unsuccessful repair attempts have been made by the dealer. I attempted to force the manufacturer to buy the vehicle back from me through the Massachusetts lemon law and since that time they have denied the existence of a problem. I have seen several instances online where consumers with the identical vehicle (all with the 8 speed transmission) complained of the same problem.

- Pembroke, MA, USA

The contact owns a 2017 GMC Sierra 1500. While driving 30 mph, the transmission failed after a complete stop. When the accelerator pedal was depressed, the rpms increased. When shifting from second to first gear, the transmission shifted into first gear with extreme force and caused the vehicle to abruptly accelerate. The contact had to engage the brake pedal with force to avoid a crash. The failure was experienced numerous times. The vehicle was taken to walsh Chevy Buick GMC (2330 North bloomington street, streator, il, 61364 815-673-4333) where the transmission system was reprogrammed twice and the electronic control module was replaced. However, the failure was not corrected. The manufacturer was notified. The failure mileage was 112. Updated 08/30/17

- Streator, IL, USA

Heavy vibration between 1200 RPM and 1500 RPM anywhere below 45 mph and above 70 mph

- Davie, FL, USA