In December of 2024 the engine started not being able to reach full power. This would happen intermittently and there would be a check engine light that would come on when this was happening. In January of 2025 I had the code pulled up by a mechanic at a local shop and this mechanic actually spoke to the service manager of the GMC dealership who said it was covered under the 100,000 mile power train warranty. I took it to the dealership who then told me the diesel mechanic was backed up and I would have to schedule repair for February. I had also received a recall notice in the mail for another issue so asked about taking of both things at the same time. I made the appointment for mid-February so had to deal with reduced engine power for several weeks.The dealership had my truck for several days and a recall was fixed and I thought the reason for the reduced engine power had been fixed also. I had received a phone call from the service representative about an issue that would cost over $1200 that I declined. I did not realize that this was actually for the main issue. I was still thinking the reduced engine power was under warranty. I got my truck back but then the next day the check engine light came on again and the engine power was reduced again. I immediately called the service representative who then told me only the recall had been fixed and that the reason for the reduced engine power was not fixed because I had declined the service. I was totally confused and didn-??t understand what happened. This is when I was told that the reason for the reduced engine power was due to a coolant control valve, which was not under the powertrain warranty. I pushed the issue and wanted answers as to why the service manager himself told the mechanic that it was under warranty and was told that the service manager is not a technician and they rely on what the technician says is the problem. And this problem was not covered. I finally gave in and got it fixed and paid $1788.

- Greenville, SC, USA

coolant control valve failure activating check engine light, reduced power mode and fan running continuously. Truck has been in the shop for 3 weeks already with no part available.

- Center Moriches, NY, USA

The contact owns a 2021 GMC Sierra 1500. The contact stated upon starting the vehicle and shifting to drive(D) in the morning, the transmission hesitated to shift to second gear and then shifted harshly. There was no warning light illuminated. The vehicle was taken to the dealer, where it was test-driven, but the failure could not be duplicated. The contact stated that the failure occurred once a day on first start-up of the vehicle and upon shifting to drive(D). The vehicle was taken back to the dealer over the weekend, and the dealer was able to duplicate the failure on first start-up of the vehicle and upon shift to drive(D). The dealer related the failure to TSB Number: 16-NA-361; and informed the contact the manufacturer had not made a repair available. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline to file a complaint. The failure mileage was unknown.

- Cheswick, PA, USA

received my truck back after replacement of the front transmission pump and idle gear, the same day the transmission had horrible down shifts, sometimes it would just downshift into neutral and bounce off the rev limiter. the service advisor told me that my transmission had to "relearn" my driving habits when I called him and would take 200-400 miles.. i drove it one more day and drove it back to the dealer to have them drive it. the agreed that something was wrong, but didn't know what and had to contact gm engineers. 2 days later they told me that the valve body needs to be replaced. I dropped it off to find out that it had been ordered with zero ETA of when they will receive it.. so now im stuck with a loaner and no ETA on when parts will be available.

- Sioux Falls, SD, USA

Reached the 100,000 mile mark and the truck started shuddering. Took it to the dealership and they tell me the torque converter is coming apart and I need a new transmission.

- Jeffersonville, GA, USA

My truck has a known recall from GMC which results in total loss of propulsion. It has not failed yet, but this is dangerous to me, my family/kids, and potentially others on the road. I have made multiple attempts to speak with GMC about the issue and also my local dealer. Neither group will provide concrete information as to when they can look at/service my truck even though there is a known remedy - [XXX] I brought my car into the dealer December of 2024 for brakes and also a rattling noise since it was uncharacteristic. Noises can be indicative of this larger problem (which I know now and didn't then) but they "didn't hear a rattle" and the "condition could not be duplicated" which is patently false since it still makes the noise/has gotten worse. Since then, I have taken the following actions: - I called and spoke with the local dealer service team on 5/5 - was told since it's showing incomplete, no remedy available there was nothing they could do - Spoke with GMC on 5/5 - they directed me to the local dealership - Made an appointment online on 5/10 to get my truck serviced and to check for this problem - They immediately called me first thing on Monday 5/12 to cancel my appointment and again tell me there is nothing they can do about this issue - I have continued to express my safety concerns to both parties - I spoke to GMC today, 5/30 and was told that there is no timeline for the issue (with my VIN) even though the remedy is known - An appointment is scheduled on 6/12 with my local dealership, but if I recall status hasn't changed, they will not check for this problem INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Duxbury, MA, USA

front idler gear for the transmission pump failed at 39500 miles. was fixed under GMC warranty. but now after getting the truck back the transmission has extremely harsh down shifts. still waiting for GM to figure out what to do next..

- Sioux Falls, SD, USA

The truck ever since of bought it has been nothing but issues. Starting with the fuel pump issues then electrical issues and most recently the coolant flow control valve. This is my work truck and now I-??m out of a truck with no loaner and the dealership has no eta.

- Delavan, WI, USA

Engine has stopped a couple of times at low speeds, Was able to restart and continue. Engine will occasionally make a "straining / Dieseling sputtering sound" when execellerating from low speeds or Stop. Transmission will make strange and strained shifts from time to time. This is reaccruing problem that comes and goes over the last approximately 2 yrs since about 9000 miles to current approx 25000 miles.

- Liberty Township, OH, USA

The transmissions in this as well as several other models of GM as well as Ford products with these transmissions are known to have major issues. My particular vehicle has major transmission shipping issues that started right around 90,000 miles or so. It started with a hard shift occasionally and has now progressed to a consistant hard shift, as well as a major shudder issue in the 35-45 mph range as well as the 65-75mph range ( when shifting into applicable gears) this has gotten worse over the last few weeks. These GM/Ford collaboration transmissions have been faulty from their inception and are well known to start malfunctioning in the 80-120,000 mile range. Please recall these transmissions so that consumers are not faced with thousands of dollars in repairs in vehicles that should last well beyond the short life span of the transmissions. I have been quoted 62-6500.00 for a replacement as there is no rebuilding these transmissions according to the mechanics I have consulted...(some have cited part availability issues as a reason). This has been a well reported problem with these vehicles/ transmissions for years now with many complaints and issues about the faulty transmissions. Just google it. I don't understand why theu have yet to be recalled.

- Benton, AR, USA

The engine coolant flow control valve position sensor is faulty. I brought mt truck in to my dealership and I have been waiting for over a month to get the issue fixed because -??the part is on backorder-??. This issue makes my truck sound like a jet engine because it makes the truck think overheating and causes the fan to come on at full blast. After drivinf for awhile it goes into -?? reduced engine power mode-?? which is totally unsafe because it reduces the horse power to that of a lawn mower. It takes about 30 seconds to get from 0-60, so merging onto freeways or in conditions where you need extra speed its completely useless and increases the scenario of being rear ended, immensely.

- Medford, NJ, USA

Vehicle is diaganosed with a coolant control valve issue. Vehicle is currently at a GM dealer awaitng replacement part and part is on back order for an undertemined amount of time. It is widely known this is a common problem with this make and year model of vehicle. This matter puts an undue hardship on me as a vehicle owner. With no known eta for this part I stand to be out of use of this vehicle for a long time. GM needs to be more accountable and attentive to their customers at a time like this.

- La Grange, TX, USA

El motor de mi camioneta falló por completo empezó a hacerle unos ruidos muy fuertes dentro del motor con solo 80,000 millas es del 2021 la compré el año pasado no llegó ni un año de uso una camioneta que supuestamente era muy buenas Estaba en el momento de lo sucedido estaba con mi mujer y mi hijo en el auto regresábamos de un restaurante acá en Miami y la camioneta se paró de pronto La camioneta fue inspeccionada por la garantía extendida la cual no asumió la reparación Luego del problema si salieron luces amarillas y rojas en la pantalla de mi camioneta

- Homestead, FL, USA

While driving on the highway the engine died forcing me to change lanes to cross traffic and coast to a stop on the shoulder. It was dangerous and unexpected. It would not restart so I had to have it towed. Inspection revealed the bearings had gone bad in the engine and the engine would have to be replaced. I had to wait 2 and half months for an engine.

- Catoosa, OK, USA

Was driving vehicle on freeway at normal speeds and the vehicle lost propulsion. Engine was off and vehicle said to shift to neutral and restart. I was able to exit the freeway safely (barely) to the median. Vehicle would not restart. It has the L87 engine which is under recall. Vehicle is at dealership submitted under the recall. I am being told there is "no remedy" and "no parts" and given no timeframe for any fix to be completed. I am still liable for the payments, insurance and this is our only vehicle in a single father of three family.

- Bakersfield, CA, USA

I was coming home after work, before I got home I stopped at the gas station to fill up my tank, after I filled up my tank I start driving home but while on my way home my truck wasn-??t speed as I expected and it only goes maximum of 10mph and I was confused, I stop and check my truck see what happens but there is no sign since there was no sign I get on my truck and start driving to home, after I got home I was trying to revers parking and that-??s when I realized my truck wouldn-??t reverse. I thought of if it happened while I was driving on highway and my truck stopped on the middle of highway I could have lost my life. I called the dealer and the dealer told me it might be because of the engine then next day I took it to the shop and they couldn-??t figure until couple days later and it took them around 2-3 weeks to replace my transmission. Luckily I had the power train warranty when I bought the vehicle and it don-??t cost anything. If I didn-??t have that power train warranty everything will come out of my pocket, the cost was around $6-7k.

- Madison, NE, USA

I've noticed rough or jerky gear shifting when accelerating, rough and reduced propulsion, loss of power. Dealership repaired power torque converter but the truck continue to have the same symptoms.

- Wheaton, IL, USA

While driving my truck with my wife and two young boys, the truck engine completely shut off while operating it. We were stuck in the middle of the road and had to cautiously wait until we could move the vehicle out of the way. The engine locked up. Now they are trying to repair the engine with the same exact engine that is on recall and potentially put me and my family in the same dangerous position.

- Concord, NC, USA

Tried to accelerate and heard a loud pop and the truck didn-??t accelerate. Pretty much went idle in the middle of the road. The check engine light, the traction control light, and the ABS light all came on. I would press on the gas and it would rev but nothing would happen till a few seconds later the RPM-??s would shoot up and you could tell it was trying to get going but didn-??t very slowly and I would hear a clicking noise every time it was around the second gear. It put my children and myself in danger because traffic was heavy with vehicles going 70+mph merging into one lane. Took it to a dealership and they stated it was the the push rod and camshaft were damaged and all 16 lifters should be replaced and camshaft also. No, the vehicle has not been inspected by any of those except a car dealership and a mechanic. This problem first appeared the day it happened and continued after. Even took it to a mechanic and had all 16 lifters changed and problem still persists. Spent over $6,000 on a brand new truck and it is still undrivable because every time you get in to drive it the cylinder #2 misfires.

- Gillett, TX, USA

See attached vehicle repair orders/Carfax/vehicle registration. The trucks transmission has been slipping/jerking hard since I pulled off the lot at dealer ship. Its burning oil no leaks has been doing so since the day I drove off the lot at dealership. I have asked to fix or address and problem still exist. They sold vehicle as everything was working The Left head light wasn-??t working the day I drove off the lot didn-??t notice until I got home I reached back out to dealer to explain and said light had a short in kept truck for almost a week said the were going to replace the head light and never did. The remote start wasn-??t working the same day i purchased the truck but sold it as everything is working. I went to try it as I was getting ready to leave dealership and did nothing. Then I discovered the fog lights were missing, and dealer said oh there was never any in the truck but if you read the service paper work there was lights in truck. Took truck back to address the issues the next day or so after purchase I was told to bring truck back the following week. All the conditions still exist and I should not be having any of these issues as the sold vehicle nothing wrong. They even had an October inspection saying everything was SAT but I get in truck no fog lights and left head lamp is not working but they performed an 360 inspection-??.yeah no way-?? This truck is doing the same as my 2021 chevy Silverado but there is nothing wrong with vehicle according to dealership. Sold A Lemon if you asked me-?? ***Highlighted in yellow is a recall that the dealership has not done nor can they find anything on the recall**** *****Power train**** Recall date 2024-10-24 Recall no. 24V797000 General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel

- Smithfield , VA, USA