2018 GMC Sierra 1500: harsh or hard shifting

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 Feb 28, 2026 · Transmission · SD

I’ve gone through two transmissions on my 2018 gmc sierra 1500 both times the same issue. The gears are shot, hard shifting. Vehicle is well maintained. Both transmissions one original equipment and second bought at the dealership the truck was bought both only lasted over 80000 miles. Driving the truck loss of power or torque is noticed, then a hard shifting. Checked fluid all was good not seeing metallic shavings. Then the overheating of the transmission, faulty valve replaced with aftermarket bypass and did transmission flush. But each occasion there was an incident I would’ve driving on the interstate and vehicle would lose power and almost hard stop and cause a crash. Then vehicle would only go in reverse both times the transmission gave out. The only warning light that ever came on was a transmission overheating and nothing else. I’m currently in the process of having to get another transmission because of the same issue again. Vehicle was seen by a technician and deemed the transmission was shot again.

Filed Jun 9, 2025 · Acceleration, Transmission · AZ

I am the original owner of a 2018 GMC Sierra 1500 with the 6.2L L86 engine and 8-speed 8L90 transmission. I began experiencing severe transmission shuddering and harsh shifting, especially at lower speeds or under light acceleration. When the issue occurs, I press the gas and the engine revs up to 6,000 RPM without reaching 20 MPH, making it extremely difficult — and dangerous — to merge into traffic or cross intersections. This issue has worsened over time and is now a critical safety concern, especially with children in the vehicle. I have researched this issue and found that many owners report the same transmission defect, and there is an open class action lawsuit and a GM Technical Service Bulletin (TSB #18-NA-355) describing the exact symptoms. The vehicle has become unsafe to drive. GMC should issue a recall or mandatory repair program for this known defect before someone is injured or killed.

Filed Jun 5, 2025 · Electrical, Engine · TX

Engine lifters failed. Heard ticking noise first day truck was purchased that gradually got louder but was told by gmc service shop it was normal to hear the ticking noise. Also when cruise control is on and you are decending a hill the rpms raise and you lose engine compression this will cause your speed to drop to around 20 mph and has happened nunerous times.. as well when making a turn sometimes or just driving the vehicle turns off while in motion and you have to coast to the side of the road and turn the key off and back on to start driving agsin.. the loss of power is a complete blackout no dash.. no engine nothing. As result of the lifter issue the engine also hard shifts in and out of slow gears.. I have not driven my truck in about a year and still owe 22k on it. The issues with this vehicle are the same as the recalled 6.3 v8 engines.

Filed Feb 5, 2025 · Transmission · NY

Vehicle jumps when shifting gears. When coming to a stop it jumps Forward. Hard shifting.

Filed Oct 2, 2024 · Engine, Transmission · NM

Engine AFM has failed. No engine light was present at the time. A loud ticking noise was noted from the engine bay. Was taken to get diagnosed, and the AFM was replaced. The problem was then resolved. Transmission has been jerking and hard shifting through the period of owning the vehicle. No diagnosis has been made

Filed Sep 3, 2024 · Transmission · 42,000 miles · NY

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the vehicle was violently shaking. While at a stop, the vehicle slammed the brake pedal, and the steering wheel was shaking. There were no warning lights illuminated. The vehicle was taken to the local dealer, where it was diagnosed that the failure was due to the transmission. The mechanic test drove the vehicle, and the vehicle was shuddering and violently shaking, and the transmission was hard shifting. The vehicle was not repaired. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 42,000.

Filed Jul 30, 2024 · Transmission · 92,288 miles · TX

The contact owns a 2018 GMC Sierra 1500. The contact stated while shifted into reverse, there was a loud clunking sound coming from the vehicle and the vehicle failed to respond as intended. The contact attempted to shift to drive(D) and neutral(N) and then back to reverse(R) however, the failure persisted. The vehicle was towed to a dealer where it was diagnosed and determined that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 92,288.

Filed Jun 25, 2024 · Transmission · NV

We purchased our 2018 GMC Sierra 1500 z71 brand new at Fairway Buick GMC in Las Vegas, NV. Pretty much off the lot we noticed some hard shifting, but over the last year/around 60,000 miles it has become progressively worse. Come to find out GM is aware of a known defect in the transmission used in this make/model and several others by GM which causes hard shifting and jerking while upshifting and down shifting primarily between 1st and 2nd gear. This malfunction has caused the vehicle to activate "limp mode" which doesn't allow the vehicle to move out of 1st gear, while driving on the road, putting the safety of the occupants and others on the road at risk. This first happened in January 2024 while we were moving and towing a 6' U-Haul trailer. Luckily we were within a few miles of our destination and made it there safely. Upon taking it to Autonation Buick GMC, we were told they had seen this issue before and the only solution would be to replace the transmission and would cost roughly $6,000-$8,000, and that's with the generous 20% discount they were willing to offer. We opted to have the transmission flushed instead and it seemed to fix the problem temporarily. Then on [XXX] while decelerating and coming to a stop light it hard shifted from 2nd to 1st then the check engine light came on and limp mode was activated. It was 110 degrees on this day in Las Vegas when my husband was driving home from work, and again by the grace of God, he was only 5 minutes from home and made it there safely. However, what if this had occurred with our two young children in the vehicle and we were no where near home? We would have been stranded in dangerous conditions potentially putting our safety as risk. This KNOWN defect in GM transmissions is 100% a safety risk and this needs to be investigated and recalled immediately. There is an ongoing class action lawsuit against GM regarding this issue and I will be looking to get involved as well. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(

Filed May 6, 2024 · Acceleration, Engine · FL

2018 gmc Seirra 1500 8 speed transmission. Making unsafe conditions while driving transmission tends to make hard shifts, jerks, hesitation when moved into gear, gets worse when stopping momentarily at stop lights and then trying to accelerate vehicle will not move. Makes hard shift and jerks then will accelerate in an unsafe manner.

Filed Sep 27, 2022 · Transmission · GA

Experienced heavy vibration or shudder through transmission once fluid got to around 145 degrees. Also transmission has rough shift on the first shift of a drive cycle. When I started to research I found many of the same issues reported with 8 speed transmissions. I’ve also read about the issues with the lifters not working for the active fuel management system though I haven’t experienced that yet. The replaced my transmission fluid at the dealership under the powertrain warranty. This issue showed up at around 35,000 miles, so I am very worried about the safety and reliability of this engine and transmission.

Filed Sep 2, 2022 · Transmission · IL

Transmission System, hard shifts and shaking causing vehicle to down shift hard and throw itself forward almost causing an accident when coming to a stop, when vehicle was taken into service they did not diagnose the vehicle for this problem, while driving vehicle shifted down so hard causing vehicle to be stuck in only 1st gear and would not shift out of 1st gear