I was driving in a city at 30 miles per hour no acceleration and no load. I lost oil pressure, dumped all the oil out of the crankcase and then the engine locked up. I had it towed to my mechanic shop that i have work done. The technician diagnosed it as a failed oil cooler pressure supply line. Where the solid steel line crimps to a rubber oil hose, that connection had not been applied enough pressure and the rubber line became separated from the steel line.

- Mcpherson , KS, USA

For the past month I have noticed my truck has been dripping oil, I pulled the shield off and saw my engine oil cooler lines leaking at the crimp points. I-??ve seen GM put out customer satisfaction notice but when I tried to have the dealership fix mine they said mine is covered under any recall or warranty. If the line comes uncrimped at highway speeds I-??ll lose all my oil where the trucks engine could lock up and lose all forward motion and in my eyes could cause a crash

- Fort Dodge, IA, USA

This vehicle shudders and vibrates during shifting and acceleration at different speeds. Transmission shifts out of gear quite often leaving me stranded at times trying to make it safely out of traffic.

- Port Arthur, TX, USA

IntelliBeam will sometimes allow me to activate the system but will turn itself off and not allow it to be reactivated until the power is cycled. Other times it will not activate at all. This is on a dark backroad with no traffic.

- Barboursville , WV, USA

Experience water leaking 3rd brake light and rear window. Leaking in both areas. Also concerned about mold that could be caused by this.

- Marina, CA, USA

UNKNOWN: Transmission/Torque Converter etc. like driving over "rumble strip. shuddering (rumble strip feel, shake), when it happens (e.g., during light acceleration between 25-?"80 mph)

- Houston, TX, USA

On or around July 12th 2025 at low speed of 2-4 mph my rear end locked up sending everyone in the vehicle hard stop forward. The vehicle wouldn't disengage leaving me no choice but to have it towed for the second time 1st time happened exactly the same about month and a half prior. Gmc service department department claims they couldn't find anything wrong after it sat for two days in there lot after having it towed they were closed weekends and looked at it that Monday morning finding no signs of anything wrong. After picking up my vehicle I strongly feel like if at higher speeds or even environment this issue will endanger myself passengers and bystanders. I need help with resolving this safety issues asap please. Gmc hasn't been much help service department nor Gm support options.

- Las Vegas, NV, USA

I washed my truck on a Saturday and as I was driving later that morning my tailgate opened while in transit. I did not notice this until I had stopped. After a little digging I found the 2019 tailgate electric switch is prone to this problem when it gets wet. There were no warning lamps for this problem.

- West Jordan, UT, USA

Bought used 2019 Denali Oct 2024 with 41 k miles on it. 1200 miles later started feeling vibration under load on highway. Took to dealership and they said I needed to replace torque converter. After that the transmission went out during test drive. Then waited 45 days for new transmission to find out the unit was defective. Now we-??re going on 5 months and the truck still waiting on a replacement transmission. GM hasn-??t acknowledged any of my complaints about this and said that they-??re doing the best they can for me and is going to award me 10000 reward points for future use! What a joke! 5. months to replace a transmission? GM has completely failed its consumers, at least this one!

- Toms River, NJ, USA

Cylinder 5 failure and cam shaft miles 78k. Have to replace full top end or brand new motor cost $10k up to $13k to fix at dealer

- Fort Atkinson, WI, USA

Rear sliding window has a leak. While washing the vehicle or if it rains, water penetrates threw the window and into the inside headliner causing water stains and mold. Water also runs down the inside of the back window to the floor carpet, also creates water stains and mold. General Motors has a Bulletin 18-NA-383, Which does not fix the problem, but only puts a temporary patch. The permanent fix would be to replace the whole window.

- Delano, CA, USA

Engine oil cooler line blew apart at factory crimp.

- Oxford, MS, USA

GMC of Vacaville California sold me a 2019 GMC Sierra that has a know back window leak issues. I was told by service worker GMC of Vacaville California sold me a 2019 GMC Sierra that has a know back window leak issues. I was told by service worker Brent Lewis/405 that is a common issue and GMC is aware of this issue that the vehicle was brought in before for this same issue prior from [XXX] but was not taken care of. I purchased this vehicle on [XXX] along with a 5k extend warranty that I was told is a bumper to bumper warranty. Come to find out it does not cover a manufacturer defected back window installation. My concern is that they are aware of these issues and water sitting on the inside of the cab due to a leak causes black mold and could cause serious illness to myself and my children. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Fairfield, CA, USA

Unknown. My truck has only about 46,000 miles. We experience heavy rains on the week of 4/8/2024 and I went to go load groceries in the back and saw water coming down the back window. I went straight to the dealer and spoke with Tom a manager at GMC. He took me to service and a mechanic came out and said this a common and expensive job. He said I may need anew window replacement. I left and did research on this problem. There seems to be EVERYONE who has a GMC or Chevy has this problem. Many people are experiencing rust, mold, etc. This is a MAJOR issue. All you hear about mold health isssues. NOT any issue that should be over look. Whenthere is water there IS mold. This issue probably has been going on longer but due to heavy rain and me going in the back I saw water. This is something that dealers need to fix.

- Riverhead, NY, USA

Purchased a brand new from dealer 2019 GMC Sierra 1500 in July 2019. I noticed not long after that time that the back window leaked once in a while when it rained. I live in Phoenix Arizona, so rain is a rare occurance and it is in the back seat area of the truck where I do not sit back there or look back there very often checking for leaks. I mentioned it to the service advisor when I was trying to get a very long running issue with the tire pressure monitors that they would not properly fix. It took nearly 2 years for them to correct that issue, and by the time they fixed that issue, truck was out of warranty and they said they had no record of this problem and they could not fix. I am worried about the water causing mold or rust up under the head liner that would cause me and my family medical issues. Water, metal amd fabric head liners do not mix and there is a water stain on the roof liner that grows every time it rains. This is a medical issue and nobody should have to wonder what is growing above their head inside their vehicle while going to work. I see many online reports of a cracked window frame on these model year trucks, so it seems to be a widespread problem with either their vendor for these windows or the installation process at the factory.

- Glendale, AZ, USA

The frame of the rear window cracked which allowed water to enter the cab. Water made its way onto the rear anchor strap of a car seat and saturated it which could have caused it to possibly not perform properly, which could have injured a child. Since the rear window can be opened electrically it is possible that a short could occur due to the water intrusion. GM has a service bulletin out about resealing the window but will not cover the repair or replacement of the window if it is outside the 36,000 mile warranty period. Obviously this is a manufacturer defect that has numerous occurrences or there would not be a bulletin created for it.

- Oneonta, AL, USA

There is a water leak coming into the back cab of my 2019 GMC Sierra. My truck smells horrible the dealership can't find the leak. It smells very moldy and very concern for my children riding in the back breathing the unsafe air.

- Mission, TX, USA

The rear window is leaking severely. It seem to be an ongoing issue with these trucks at the rear brake light spoiler. It-??s a substantial amount of water and there is water damage and mold.

- Coral Springs, FL, USA

Water getting in cab

- Elko , NV, USA

2019 GMC Sierra 1500 Limited transmission problems could include shifting delays, grinding when accelerating, the car shaking on the road

- Tavares, FL, USA