2018 GMC Canyon power train problems

“On many occasions, over several years of ownership, ''NEW in 2018, the trans has had violent shift Problems. I could only find 1, ONE instance where a person was "injured'' by ANY of the GM 8L transmissions. My neck is hurting Now. I'm compelled to do this for Others who been Scammed by GM as they still sell a 8 speed rewrapped. I can't believe this has been protected against being called a SAFETY ISSUE By any Gov. agency. I got my truck in Retirement and Know I can't and won't Tow a Trailer or Boat Like I planned to. If I cause a wreck, Knowing the Defect, I will be held Responsible, Not GM LLC. It just did something new on 7/23/26. it stuck I a mid range gear and wouldn't shift, I Bumped it into Neutral to slow down and Recover proper control. I've said enough, be safe if you Have an 8 Speed from GM, or a 10 speed too.Read UP.”

“This is a known problem with GMC and Chevy trucks, known as the Rumble. At approximately 45mph and up, the truck feels like it’s going over rumble strip and the back end is slipping. This causes the steering wheel and truck to shake. It could result in the loss of control if it gets too bad. I took it in for diagnostic testing, which confirmed that it was the transmission. They recommended a triple flush and replacement of the transmission fluid, as well as a computer upgrade. I had them complete the recommended service. As of right now it seems to have helped. But if it returns the next steps is to replace the torque converter. There were no warning lights, nor messages indicating an issue.”

“The contact owns a 2018 GMC Canyon. The contact stated that while driving in the snow, the 4WD function became inoperable, and the vehicle lost traction and started skidding. The "Service 4WD" message was displayed. The vehicle was taken to a dealer where it was determined that a chip inside of the casing of the 4WD feature was inoperable. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 40,000.”

“The contact owns a 2018 GMC Canyon. The contact stated that while driving at an undisclosed speed, there was an abnormal knocking sound coming from the engine compartment. No warning lights were illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the transmission. The contact was informed that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 34,929.”

“The transmission is sluggish and jerky resulting in unpredictable and inconsistent speed control. The vehicle is available for inspection, if requested. The inconsistent speed control is a potential hazard during acceleration and deceleration. The issue is known to the manufacturer. No warning lamps or messages have been observed. The symptoms began to appear soon after the vehicle was purchased on 12/28/2024.”

“Major potential for deadly fire or explosion. Fuel tank strapped failed after forward strap bolt fell out of threaded cross member where fastened in frame. The failure led to the fuel tank hanging inches off the ground on the freeway stressing fuel pump lines to forward upper tank. Metal grinding noises heard to prompt roadside inspection confirming hanging, unsecured tank full of 26gal of diesel. The tank wedged the fuel tank strap between plastic tank and drive shaft (propeller shaft) with heat and potentially spark as the the metal strap ground into the drive shaft marring and striating the durable metal. Heat and plastic melts, heat and spark with diesel combusts..in addition to risking of dragging tank at highway speed rupturing tank. Upon service at the dealer, mechanic observed the rear bolt to fuel strap was also loose and needed to be secured. GMC Protection Plan denied compensation for coverage as they do not cover "bolts, fuel straps, or manufacturer defects" under advertised "Bumper to Bumper" GMC Protection Plan marketed by GMC dealerships as protection for all non-wearable parts. No warning indicators appeared. My dog was in the truck bed in a…”