While driving with the roads in a wet condition, for various lengths of time, and in different maneuvers, the service engine light will start flashing and the vehicle will begin to lose power. After a few minutes, the service engine light will go solid and the traction control light will illuminate. The vehicle loses more power. On braking, just before the vehicle comes to a complete stop, there is a clunk in the transmission and the vehicle lurches. This has occurred 6 times in the last 14 months. Upon investigation, trouble code P0308 shows in the obd tool. The issue could not be reproduce by the dealership so there has not been any resolution, just thoughts.

- South Lyon, MI, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that a coolant smell would emit from the vehicle upon exit. The contact also stated that his vehicle had began to lose coolant at an abnormal rate and had to be frequently replaced. The contact took the vehicle to mcconnell automotive (3150 dauphin St, mobile, al 36606) where they confirmed that there was a crack in the radiator which resulted in a coolant leak. He was also informed that there was no recall on the VIN and that the warranty did not cover the repair. The manufacturer was notified of the failure and provided the same information as the dealer. The vehicle was not repaired. The failure mileage was approximately 42,000.

- Irvington, AL, USA

The radiator is leaking coolant without any real cause and I was told the entire radiator needs to be replaced.

- Knoxville, TN, USA

I have had my GMC Sierra 1500 for almost 3 years. I have a little under 59,000 miles on the truck. A few thousand miles ago a tech at the GM dealer let me know that they had to add some coolant and it was something I should keep an eye on. I brought the vehicle back to have them look into it. They let me know that the radiator has a small leak. It is not big enough to have fluid hit the ground in my garage but it is loosing fluid. I looked online and saw that this is a common issue. I was told that it was not covered under warranty and it would cost a good amount to fix. I have had this vehicle for under 3 years and have had 5 issues without any of them being covered by warranty. This vehicle seems to be a lemon.

- La Crosse, WI, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at various speeds, the temperature gauge indicated that the vehicle was overheated. No warning light was illuminated. The vehicle was taken to beck & masten Buick GMC North (11300 fm 1960 West, houston, tx 77065, (877) 380-8433) where it was diagnosed and determined that the radiator was leaking coolant and that the radiator needed to be replaced. Coolant was refilled in the vehicle. The dealer contacted the manufacturer for assistance with repairs. The failure mileage was approximately 47,000.

- Spring, TX, USA

After long periods of running and idle, vehicle stalls out has a hard time restarting. Gas paddle being press helps sometimes. Check code P2635 plus others (random secondary codes), come on. This has taken place in AZ where the ambient air temperature typically is over 100. Vehicle has been to GM dealer who says its vaporizing the fuel in the lines. Tsb pip5507B dose not include 2018, however the design hasn't changed. Conditions; long idle, hot weather, low speeds under 25 mph or idle. Location; AZ sonrona dessert, off-road, jobsite, city streets.

- Phx, AZ, USA

Bucking and surging when switching gears. Hard bang when trying to switch. Surged forward at a complete stop.

- Dracut, MA, USA

No transmission power regardless of the gear shifter position. I turned the engine on and off several times trying to get a solution, no luck. I returned to the vehicle 5 minutes later and did get it to move, ,,would only go 25 mph at 3000 rpms. I was in the middle of wi not near any major dealership on-star was useless saying I had a major engine problem and the computer was trying to protect the engine. I was directed me to a Chrysler dealer ship, who told they could not get me in for 2 weeks, suggested another branch which was over 45 miles away. I drove 5 miles to a friends house and was able to find a dealership in janesville, wi (fagan). When I started the vehicle to drive to janesville, the transmission did work. Fagan spent 2 hours working on it, and could not find a cause for the problems, they checked every computer, could not duplicate what happened. They reprogrammed all the computers. Then in cincinnati, oh the power steering assist went "off", while staionary. I tried restarting several times to no avail, drove the 3 miles left to the G'kids house, no power steering, trailer problem lighjt on, no RPM or mph needles moving. Called local dealership (borcharding) and they suggested I drive it to their location 12 miles away. When I started it, the power steering was back on, but the unit would not get out of 2nd gear, ran 40 mph at 2500 RPM, warning lights all on, engine light still on. Next moring I started the vehicle, everything was okay including the transmission problem, but still had the "check engine on", the dealership kept it (2) days, involved GMC engineers, could not determine the cause for all the problems, including loss of "steering assist". they drove it over 50 miles on two trips, could not duplicate what happened. They told me it was some kind of computer problem, but could not determine, they reset everything again.

- Delavan, WI, USA

Fuel injection seals #4 O-ring split - leaking fuel - pooling gas on manifold. Took vehicle in for smell of gas, lack of acceleration and poor gas mileage. This is known issue based on the service bulletin 18-na-137 - vehicle has less than 6000 miles

- Inver Grove Heights, MN, USA