After noticing a "groaning/moaning" sound from the vehicle when turning sharp at low speeds the vehicle was brought into a dealership to be inspected. After inspection, the mechanic stated that the sound is coming from the rear differential and that it would need to be flushed/cleaned up to three times as a potential correction. If the clean/flush does not correct the issue, they would need to replace the entire rear differential. When asked what happens if the rear differential fails, we were advised that we could experience total failure and lock up. This is a safety issue in that if we are driving and the wheels lock up the potential for collision or major accidents is high. I also understand that the differential is meant to last the life of the vehicle and had 123k miles, the life of the vehicle is far from over. Another issue we are experiencing is excessive oil burning. The vehicle "add engine oil" light comes on after 2,500 miles when being regularly maintenanced. The vehicle should not require the addition of oil after that many miles, more so should not require oil at all unless you weren't properly maintaining the vehicle (which is not the case). I understand issues arise and things happen; I just want this to be acknowledged as a potential safety issue and corrected. Thank you,

- Ricon, GA, USA

I-??m not happy with just a change in oil viscosity because the car has already been on the road for 70000 miles before we were aware of the recall on the engine. Changing the oil viscosity doesn-??t help when there is a underlying engine problem it should be replaced not just change your oil and send you on your way because now I-??m always wondering and worried if the engine will still fail when my kids and wife are in the car. Furthermore I just had it inspected and the oil changed to new viscosity a week ago and the oil level is already half way on the dipstick so I-??m taking back to the dealership to express my concern. If I would have known this was going to be an issue with this suv I would have purchased something else. I-??d just like the engine replaced so that I don-??t have to worry every time I pull out of the driveway with my family. My power steering assist still whines and there is no open recall on it. I think GMC should be responsible for replacing engines and power steering assembly and power steering motors on 2021 GMC YUKON DENALIS because of the wear and tear they have endured before the recall was taken care of by adding a different viscosity oil because the damage has already been done.

- Dade City, FL, USA

The contact owned a 2021 GMC Denali. The contact stated that while his wife was driving at 25 MPH, the vehicle lost power steering. The vehicle failed to turn and crashed into a tree. There were no reported injuries. There were no warning lights. The contact stated that the failure was related to NHTSA Campaign Number: 21V455000 (Steering). The vehicle was taken to his residence. There was no police report filed, airbag deployment, or fire. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The insurance company deemed the vehicle to be a total loss. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 67,000.

- Minnetonka, MN, USA

The contact owns a 2021 GMC Yukon. The contact stated while driving approximately 20 MPH, there was an abnormal sound coming from the vehicle while turning right or left. No warning light was illuminated. The vehicle was taken to an independent mechanic to be diagnosed; however, a diagnostic result was not provided. The independent mechanic made the contact aware of an undisclosed recall however, the VIN was not included. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 76,052.

- Atlanta, TX, USA

-??Service steering column-?? notice appears on dash board. Steering wheel is locked and car won-??t start leaving us stranded. Dealer could not diagnose problem. Car started at dealership. Took it home. One month later happened again.

- Watrenton, OR, USA

This GMC Yukon underwent an over the air update in remote Wyoming and was almost undriveable due to steering problems and brake malfunction. Also engine and transmission problems. It has been awaiting repair, but I have been informed that no fix is available because of transmission defect. No parts available We were nearly stranded.

- Missoula, MT, USA

Out of no where the right side makes a clicking noise when I turn

- Southfield, MI, USA

After pulling out from parking lot into roadway, steering wheel locked up (right) and vehicle proceeded uncontrolled into a telephone pole - injuring driver. Driver stage 1 & 2 together with seatbelt pretensioner deployed upon impact. No warning lamps or defect symptoms prior to time of failure. Inspection revealed DTC codes for power steering of U0420:00 (invalid data received from power steering module) and U3000:49 (control module internal malfunction). Scanner evidences power steering position sensor data not being reported. Vehicle VIN indicates that it was included in NHTSA recall 21V455000. Power Steering Component Part Nos: 85103817, 848935231 and 85116776.

- Dallas, TX, USA

Hello, I am a Repair Technician for a General Motors dealership in Reno NV. vehicle in question has no ability to to placed in neutral without the engine running. per GM repair guides the vehicle must either be placed in neutral with engine running or a special tool is needed to placed trans into neutral in to move vehicle. this is a major safety concern as vehicle became engine became disabled and the vehicle could not be moved. steering is locked, parking brake automatically sets and neutral position on gear selector cannot be selected. this happened at our dealership. but i can only imagine this happening to someone on the highway. stuck blocking the road with no ability to move the vehicle to safety. i feel this is extremely dangerous and i am sending an email to General motors technical assistance also.

- Reno, NV, USA

The vehicle was stationary and upon turning it on a message showed up on the display stating to immediately take the vehicle for service and to drive carefully because of a power steering issue. Once the vehicle was placed in reverse to begin to leave the parking spot, it was evident that there was no steering available on the vehicle. It would only move forward and backwards but the steering wheel would not move in any direction at any degree making the vehicle impossible to drive safely or carefully to any location. Attempting to drive the vehicle for service would have caused an accident and ultimately was impossible so we decided to have the vehicle towed. The dealership service department informed us that this was a problem with the system/software and that the vehicle had many more history codes for this issue. After informing us that the update for the steering system was completed, they also said it may not be the fix based on the multiple history codes. The car is still being inspected as they are unable to be sure the cause or that it will not occur again. Records of service can be provided once the vehicle is returned to us and messages of communication with the service department can also be provided upon request.

- Marietta, GA, USA