Automatic Transmission Torque Converter problems of the 2018 GMC Sierra 1500

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the transmission vibrated. No warning lights were illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed with a failing torque converter. The contact was informed that the torque converter needed to be replaced. The vehicle was not repaired. In addition, the contact was informed of a manufacturer's warranty. The contact was informed of a manufacturer's warranty for the 2018 GMC vehicle's transmission failure due to the incorrect oil being used during production of the torque converter. The dealer was made aware of the failure; however, the contact was informed that the manufacturer needed to approve the repair coverage. The manufacturer was made aware of the failure but provided no assistance. The contact was advised to contact the NHTSA hotline to report the failure. The failure mileage was approximately 89,000.

After cold starts when accelerating the transmission slips from 1st to 2nd and throws your body forward. After that first gear change it doesn't do it again until another cold start. Around 34000 miles I am getting a rumbling vibration through the dash and steering wheel when holding speed between 35-75 mph. The rpm guage will jump slightly and it will feel like going over rumble strips. Acceleration is very weak at times. Sometimes its ok. There has to be something done with these torque converters and transmissions by gm. Unacceptable for a 40-50k dollar truck!.

Purchased vehicle brand new from dealership and from day one, I notice the power train slow to shifting from gear one to two. The vehicle hesitates and sometimes shifts hard only during cold starts. Every time I take it in for my schedule service I report the same issue to my service advisor along with the service manager at the GMC dealership. They say that it is a normal problem and they know about it. The last schedule service I told them about the same problem, this time his service tech test drove vehicle and said torque converter was shuddering causing vibration. The solution he said they changed the transmission fluid. Today I still notice the same issue and will report to the dealership next time I take in for service. I have read this is a common problem from the manufacture since putting in an 8 speed transmission. I feel this is a safety issue and some day I may feel that the transmission may lock up on me and may cause an accident.

When truck is in motion shifting from reverse to first/second gear it jumps forward into gear. There is a hesitation shifting into gear. It is a very well known problem with the 8 speed transmission. I have been in contact with the dealer but 3 different times. The know the problem as does GMC. They actually can fix the problem. But will not do anything until GMC sends out a technical bulletin. There has been an unbelievable amount of complaints. I understand GMC is hesitant because they may have to replace transmission and or torque converter which would naturally cost a lot of money. But also I understand changing to a different transmission fluid will help. But dealer will not do it. This has been going on since the day I bought it brand new and I only have 5700 miles on it. I have not had accident because of this. But concerns me with the hesitation and jumping in to gear. Also it does not do it every single time. Depends on your take off speed.