We’ve been watching the General Motors 8-speed transmission in the GMC Sierra 1500 and Chevy Silverado 1500, and in addition to several complaints about sudden shifts and hard jerks, there is a lawsuit pending. Now we hear for 2021 models, at least, GM has announced a Customer Satisfaction Program for some vehicles that involves replacing the transmission.
Ostensibly, these two issues don’t look related. According to GM Authority, the problem here is that the 8-speed automatic transmission may have broken a carrier ring. As that publication states, a broken carrier ring could prevent the transmission from operating as intended.
So, GM is going to replace those transmissions with a new one at no cost to the owner.
We’ve reached out to GM to see if we can get our hands on the original communication regarding this Customer Satisfaction Program, but at the time of writing this story, our contact hadn’t been able to source it for us yet. In fact, the only reference we’ve found anywhere on the web to the Customer Satisfaction Program number N21232809, is in the GM Authority story.
We do, however, know that this program only covers 90 (yes, ninety!) trucks. We also know this transmission issue is not listed on the NHTSA website as a recall or a tech service bulletin.
The bottom line on the GM 8-speed transmission
There’s seems to be lot going on with this transmission, and while the GM 8-speed transmission isn’t in every Sierra and Silverado, it’s going to be in a lot of them – especially the less expensive models since this transmission is most frequently paired with the 2.7-liter turbocharged engine.
Right now this is only applying a minuscule number of trucks, but we’ll be curious to see if it widens out eventually — or if there’s something else altogether that will pop up. So, we’ll continue to keep an eye out for more developments on the GM 8-speed transmission drama.
My 2021Silverado 8 speed is having intermittent clunks into low gear at stop lights. I have not received the recall notice, I was told that the newest 8 speed s were good, BS!
I have a 2019 8 speed and it had the same annoying thud into gear at low speeds. Stop and go style driving would often cause the thud to happen. It seems to have softened up by itself a little bit over time.
Like you said GM made several improvements to the 8 speed for the new generation 2019+ Silverado meant to improve shift quality including a modified torque converter, but it seems it didn’t get the job done.
My 2021 brand new Chevy Silverado RST Z71 1500 with 6,680 miles on it just blew the transmission!!! Seriously 8 speed isn’t fixed I’m stuck in a loaner car they are currently tearing down my transmission! Never even went on a gravel road and just made my 2nd payment the day before it went down ! NO WARNING NOTHING , parked at Sams club ran in came out started my truck and put it in drive and nothing ! RPMs went up and I went NO WHERE! Put it in reverse NO WHERE! Had to call a tow truck ! I’m not happy at all for what was paid for this truck !!!
it just happened to my 2021 Silverado trail boss at 650 miles. I was a couple hours from home and had to have it towed.