GMC Sierra 1500 harsh shifting problems

Filed Oct 6, 2026 · Driver assistance, Transmission · OH · fire

I was driving at 70 mph on the highway. I heard clunk and then rattling and saw smoke while losing power. Check 4wd warning illuminated. Came to stop in busy traffic and where I first parked on shoulder, saw shoulder of roadway smoking and on fire. I pulled forward 100 or so feet slowly while hearing more grinding rattling cranking. Came to stop. Fire dept arrived and extinguished roadside blaze. Called towtruck and had towed to [XXX] in [XXX]. 75k miles. No warning just catastrophic failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 5, 2026 · Transmission · 38,000 miles · FL

The contact owns a 2021 GMC Sierra 1500. The contact stated that the transmission was previously replaced. The contact stated that 20,000 miles later, the vehicle started to experience erratic hard shifting while driving at various speeds, and the vehicle failed to respond upon shifting into reverse(R). The vehicle was towed to the dealer, where the battery was replaced; however, the failure recurred. The contact received notification of the federal safety agency Campaign Number: 24V797000 (Power Train). The vehicle was towed back to the dealer, where it was determined that the transmission needed to be replaced. The contact was advised that the repair was not covered under the extended warranty coverage associated with the recall because the required DTC was not retrieved. The contact advised the dealer to complete the TCM software update under the recall, which would enable the generation of warning lights and DTC. After several attempts, the dealer informed the contact that the TCM software update was unsuccessful. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was notified of the failure by phone and email, a case was filed, and documents were sent to the manufacturer. The failure mileage was approximately 38,000.

Filed Sep 24, 2026 · Transmission · CA

I own a 2021 GMC Sierra 1500 AT4 with the 3.0L Duramax diesel. The vehicle developed severe transmission problems, including harsh/jerky shifting and a hard clunk when shifting into reverse. The vehicle was subsequently diagnosed with an internal transmission failure. The repair facility informed me that the transmission gears had failed and caused damage to the transmission and stated that the failure appeared to be related to a manufacturing issue. The repair facility also advised me to watch for a future recall because they believed this could be a widespread issue occurring in other vehicles. I am submitting this complaint so the failure can be documented and considered along with other reports of transmission failures involving this vehicle.NOTE FROM AUTOSHOP:TRANSMISSION FAILURE WAS DUE TO A MANUFACTURE DESIGN FLAW, NOT DUE TO THE CUSTOMER'S DRIVING HABITS. THE PUMP ORIGINAL DESIGN IS WITH SLANTED GEARS AND THE GEARS ARE FORCED AWAY FROM EACH OTHER AND PLACING TOO MUCH STRAIN THE BEARINGS ANI THE BEARING FAIL. AN UPDATE PERFORMED TO HAVE STRAIGHT CUT PUMP GEARS TO AVOID BEARING DAMAGE. CDF DRUM AND CENTER SUPPORT CHANGED TO UPDATED PARTS THAT ARE HEATED TREATED TO AVOID DAMAGE

Filed Sep 17, 2026 · Transmission · CA

Vehicle purchased Certified Pre-Owned in October of 2021 with roughly 43,000 miles. During the first service (47,598 miles) at a GM dealer I reported very hard shifts, but this issue was ignored during service. At the next servce (54,571 miles) I again reported the hard shifts and "surging" when coming to a stop but the dealer reported they were unable to replicate the issue and did not address it. At the next service (61,620 miles) I reported the issues with the transmission once again and this time they performed a transmission fluid flush/replacement, acknowledging the issue and asking me to drive for 200 miles and return if the issue was not fixed. I returned at 62,058 miles as the issue was not resolved and they replaced the torque converter. During my next visit (68,709 miles) I reported the issue was still present but was informed they would not address it as I was now outside of warranty. I reported this to GM but was told to pay for a diagnostic and repair and "hope" that the dealer would elect to cover it.

Filed Sep 9, 2026 · Engine · 12,998 miles · TX

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving 65 MPH, the engine made a clunking, knocking, and tapping sound. The engine was driving on seven of the eight cylinders. The contact slowed down and pulled over. The engine warning light was illuminated. The vehicle was taken to the local dealer and was diagnosed with a detached valve. The vehicle was repaired under an extended warranty. The dealer informed the contact that the failure might recur. The failure mileage was approximately 12,998.

Filed Aug 28, 2026 · Engine, Transmission · SC

Truck went into limo mode while driving and required valve in transmission to be replaced. Went from driving normal speed to only being able to go about 15 miles and hour. Was repaired got the truck back and the next day was on the interstate in the fast lane and the truck again had speed issue reduced speed and had to coast off interstate. This time entire valve body had to be replaced. Have gotten truck back and still have hard shifting in the transmission at times. Engine was checked for recall and now I have to pay a much higher oil change price due to a GM issue. This was not a known cost when purchasing this truck.

Filed Jul 29, 2026 · Transmission · NC

My truck is at the dealership for a failed transmission valve body. I was doing some research on this issue and saw recall N242454441. I asked the service writer about this and he said my truck was not covered by the recall. I had all of the same issues as described in the recall. effects can cause harsh shifting, setting a service engine soon message, reduced engine performance or P0747 diagnostic trouble code. I was driving along when the check engine light came on then a message on the dash said reduced power mode. I barely made it to work then called the dealership and told them I was bringing it in if I could make it. When I tried to take it to the dealership the rear wheels seemed to be locked up when in drive but would move in reverse. After coasting forward in neutral then reversing the wheels seemed to unlock in drive but then I didn’t have reverse. I have the same drive train with the 10 speed transmission. I think this recall needs to be expanded to include my truck as well as countless others for this known issue.

Filed Jul 9, 2026 · Transmission · TX

transmission shuddering, harsh or delayed shifting, and erratic gear changes. The truck jerks really bad during each shift of the ten speeds. A vibration or shudder typically occurring at speeds between 25-65 mph under light throttle. Also makes a bad noise every times it’s shifting. I have no lights on the dash and the gmc app tells me everything is fine when clearly it’s not . I see there’s a recall for my year and make but for some reason my vin doesn’t fall in the category

Filed Jun 15, 2026 · Transmission · PA

Issue is with the transmission as it harshly shifts into a low gear when on an incline. This causes me to lock up my breaks as it feels like the truck was rear ended by another vehicle. I’m concerned that this is going to cause an accident. This problem has not been reproduced by the dealer. I’ve taken it to the dealership several times. No warning lamps or messages.

Filed May 21, 2026 · Engine · SD

After the vehicle was purchased in October 2023, it immediately had an issue shifting very hard. After numerous trips to the servicing dealership in attempts for error codes to be discovered with no success, the dealership gave the recommendation to flush the transmission as this was a fix for this type of engine in November 2024. The transmission was completely flushed in November 2024. The vehicle continued to have the issue with hard shifting and also developed less efficient gas mileage and would misfire upon ignition and there was a constant knock when running. After a prominent ticking began in May 2026, it was discovered that the timing chain was broken and we were told the rods could impale the engine and go through the hood if the engine was not replaced. The engine had completely failed and needed to be replaced including radiator and hoses. The engine, radiator, and hoses were replaced 05/2026. The invoices for both of these Service transactions are attached. After much research and advice, it appears this issue was the same issue that was happening with the other 6.2L L87 engines from the years 2021 to 2024 that were recalled.