2019 GMC Yukon Xl

Vehicle started showing a po308 code. Called sewell gmc In midland where I purchased the vehical they were 2 months out on diagnostic services. So I took it to another shop. They ran a camera into the problem cylinder and for scaring on the walls. They said it was due to the afm system and the engine was unrepairable. So now I am out 17,000 dollars and stranded over 700 miles from my home due to a manufactured defect.

The contact owns a 2019 GMC Yukon XL. The contact stated that on several occasions while stopped and attempting to accelerate, the vehicle reversed inadvertently and then jerked forward to accelerate. The contact added that the battery was drained but the failure was not the most important to report at this time. The vehicle was taken to a dealer where it was diagnosed that the starter needed to be replaced. The issue reoccurred the same day. The vehicle was taken to the same dealer where it was diagnosed that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 135,000.

The transmission is shaky, Lower gears the truck seems to fight it way into the next gear, I feel this is happening around 3 to 5 gears. One garage told me the power converter was failing. I changed the transmission fluid and filter and it got better, but sill, this is an expensive truck. This is power train, this should be covered to 100,000 miles.

The vehicle experienced a lifter and valve train failure within the warranty period, as addressed in GM TSM MC-10209953. This failure can cause sudden engine noise, loss of power, and potential engine seizure while driving, creating a serious safety hazard for the driver, passengers, and others on the road. The component failure is reproducible and has been confirmed by a repair shop; it is available for inspection upon request. An engine rebuild was completed just after the warranty expired, and the manufacturer has denied warranty coverage and refused to address the issue. Prior to failure, no warning lights or messages indicated a problem, meaning drivers have little to no warning before a potentially catastrophic malfunction. Because this is a documented issue affecting multiple vehicles and the manufacturer is refusing corrective action, this defect presents a clear risk to public safety. I urge NHTSA to investigate this matter, determine whether a safety recall is warranted, and require the manufacturer to address this known defect to prevent accidents and injuries.

2019 GMC Yukon XL. Purchased pre-owned from a dealership in July 2023. This month, August 2025, my transmission has failed. Apparently this defect is notorious for this particular year of GMC Yukon XL. There was a lawsuit against GMC but it was closed in June 2025. The issue is real and widespread and GMC should ABSOLUTELY be responsible. There’s no reason a six year old vehicle should require this extensive repair.

December 28- Transmission goes bad, gets vehicle back Feb 17th - •Dangers include loss of vehicle control, wreck, cannot hit gas pedal. March there’s an exhaust leak. •Inhaling is dangerous as this contains carbon monoxide, potential fire, May y axle on muffler •Dangers include reduced engine performance that can lead to wrecks, carbon monoxide poisoning, and failed emissions test. July Engine failure in repairs until August •Can cause accidents August coolant leak •Can lead to engine overheating and lead to engine failure causing accidents. September unknown reason, car just keeps shutting off while driving. •Dangers in this one speak for themselves. Inspection can be done. Problems were confirmed but just keep continuing to occur. No warning signals, car just keeps breaking down for various reasons.

The contact owns a 2019 GMC Yukon XL. The contact stated that while reversing out of the driveway at approximately 2 MPH, the vehicle stopped moving. The contact depressed the accelerator pedal and the vehicle only revved. The contact stated that she was able to move the gear shift lever, however the vehicle was not responding in any gear. The contact stated there was no warning light illuminated. The contact had the vehicle towed to a local dealer, where it was diagnosed and determined that the transmission had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 78,000.

GM vehicles manufactured between 2015 – 2019 equipped with GM’s 8-speed transmission are equipped with a defective transmission design of GM’s Hydra-Matic 8L90 transmission or Hydra-Matic 8L45 transmission, which causes vehicles to suddenly lurch forward, shudder, and experience significant delays in acceleration. GM not only knew about this pervasive issue but developed a fix for it in 2018 – namely a transmission flush it calls Mod1a. However, GM made the business decision in 2019 to forgo recalling all impacted vehicles (approximately 2 million) to receive this flush, which would have cost GM about $305 per vehicle for a total $592 million, and instead decided to limit the flush to only unsold Cadillacs and trucks in certain states where it expected customers to complain within their warranty. Furthermore, GM never alerted existing customers of the issue or the fix and only addressed the issue if the customer was under warranty and complained about the shudder. GM marketed and sold these 8-speed automatic transmission vehicles as having “world-class performance,” lightning-fast and smooth shifting, along with improved fuel efficiency, and instead sold defective vehicles.” These conditions make it difficult to safely merge into traffic or back out of a garage/driveway. Even more troubling, the transmission defects cause the vehicle to delay downshifting and decelerating when the brakes are depressed. The affected vehicles include Chevrolet Silverado (2015-2019); Chevrolet Colorado (2017-2019); the Chevrolet Corvette (2015-2019); the Chevrolet Camaro (2016-2019); the Cadillac Escalade and Escalade ESV (2015-2019); the Cadillac ATS, ATS-V, CTS, CT6, and CTS-V (2016-2019); the GMC Sierra, Yukon, and Yukon XL, and Yukon Denali XL (2015-2019); and the GMC Canyon (2017-2019).