2021 GMC Sierra 3500 problems

“During takeoff the transmission acted as if it was in neutral while I was crossing traffic luckily, the semi truck that was coming towards me was able to stop. I had the vehicle towed to a shop. After the vehicle was towed to the shop the transmission acted normal when the mechanic searched the VIN number. There was a service bulletin issued by General Motors for this exact problem. Had the semi not been able to stop. It could’ve very well killed me or my children. I suppose if it would’ve killed someone, maybe general motors would finally do a recall for this very disappointed in general motors and the NHTSA, the fact that this is an ongoing problem and has not been fixed and as a customer, I was not even notified that this problem existed is very alarming.”

“The contact filed the complaint on behalf of the owner of a 2021 GMC Sierra 3500. The contact stated that while the vehicle owner was driving at an undisclosed speed, the driver noticed that the rear wheels were attempting to lockup. The contact stated that the failure was noticeable while driving forward and while reversing. No warning light illuminated. The vehicle was taken to the independent mechanic, where it was diagnosed with detached rear brake pads and detached rear emergency brake shoes. In addition, the rear brake caliber had seized. The vehicle owner was informed that the rear brake pads and the rear emergency brake shoes needed to be replaced, and the rear brake caliber needed to be repaired. The vehicle was repaired. The dealer was made aware of the failure. The contact was advised to contact the NHTSA Hotline to report the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 140,606.”

“The contact owns a 2021 GMC Sierra 3500. The contact stated that while his wife had the vehicle idling with the rear defroster activated, shortly afterwards, she observed smoke coming from the plastic on the rear sliding window. After a visual inspection, the contact's wife observed that the plastic was melting, prompting her to deactivate the rear defroster. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 26,000.”

“Multiple instances of diesel engine emissions system parts and software failure. While driving, towing or not, the DIC would randomly display a message that the DEF level is low and reduced speed will occur in x-amount of miles and that mileage would then begin a visible countdown on the DIC, sometimes much more quickly than the actual speed I was traveling. In other words, it might at first state 500 miles remaining, but then be counting down from 500 miles by one mile per second of time, or faster. Each instance, I would park and attempt to refill the DEF tank, only to discover that the tank is already full or near full. My truck’s DEF tank has now been replaced twice under warranty with the latest tank being installed at only 35,460 miles on the odometer. During the latest replacement, the technician also diagnosed and replaced the electrical wiring harness related to the DEF tank, stating that one of the connector pins was not reading the required voltage. There was also a faulty diesel particulate sensor that was replaced under warranty. This emissions system is problematic, and it is unsafe to due to the drive ability restrictions it imposes due to faulty…”

“Part Number: 85138746 - DEF tank assembly, heater, pump, reservoir. I was told there were issues with the heater and pump. The heater turns high or the heater won’t work; and there are issues with the connector.02/24/22: My truck has 16,000 approx. miles. The check engine light came on and displayed message that I had so many miles until truck would be restricted to 65MPH. I took my truck into Kendall dealership in Nampa, Idaho and was told there was myself and another person who had the same issue. A couple weeks go by and I call the dealership back and was told that I was 5th in line and there were 20 behind me. I was told that there were 11,000 parts already spoken for and 6,000 parts on backorder. I was one of the backorder individuals. I was also told that they do not have a ETA on when they would receive parts and that parts show up unexpected. They told me that I would have to contact GM customer service for assistance. The dealer called me back March 31st to see if I got my camper moved and how much it cost to move. They told me the dealership would cover one month truck payment and would like me to send in my loan payment statement. I asked for…”