2019 Transmission vibration and shifting issue

GMC Wizard

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Hello all,

My 2019 AT4 is experiencing transmission issues at lower RPMs (1500 ish) when the throttle is only slightly open. It feels like I am driving over small rumble strips. The shifting is also not smooth and kind of "clunky" at slower acceleration. Anyone else experiencing this and if so what did you do to fix it? Thank you!!
 

Also have a 2019 5.3/8 speed. Mine is kind of clunky 1/2 gear when babying the gas. Never have experienced the rumble you describe but it is very random when the truck acts up. I try to use the skinny pedal a bit more than let it idle through 2nd gear.

Hope I'm not sorry about not getting another Toyota, my 13' Tacoma was solid and I would still be in it if the rust didn't start eating it up.

My fix was getting the extended warranty and hopefully I don't need to use it.
 

I was actually coming on here to write about my transmission issues, too. I have a 2023 with the 6.2 engine. For the first 9ish months of ownership the trans was perfect… could almost never tell when it changed gears, and putting it into Park was the same - couldn’t feel a thing. Starting about 3 months ago when I would put the truck in Park, I would get a clunk and could feel it through my feet. Took it to the dealer at around 8,500 miles and they said they couldn’t replicate the issue, go figure.

Now at just barely past 11K miles, I’m getting rough shifting at lower speeds and sometimes it’s getting stuck in gear when I take my foot off the pedal to coast before slowing down for a stop… the rpm will just hold around 2,000 for like 5-8 seconds even though my foot is fully off the pedal. And now putting the truck in to Park will sometimes clunk so hard it throws my shoulder off the seat by a full inch. But it’s so sporadic. Sometimes I can put it in to Park and it’s smooth as butter… can’t feel anything happen, and then the next 2-3 times parking in the same exact spot in my driveway it’s that awful clunk and makes the whole truck jerk, then the next time it’s flawless again. Doesn’t matter how I do things - foot fully on the brake and making sure there’s no rocking back and forth; putting on the parking brake first or not putting it on first; level ground; incline ground; decline ground… there is no rhyme or reason to when it does, or does not, happen.

Taking her in to the dealership again tomorrow, and if they tell me again that they can’t replicate the issue, I’ll probably trade her in. I’m about to make a couple 1,800 mile drives, and I’m not doing that with a vehicle whose transmission I have no trust in any longer.
 

Hello all,

My 2019 AT4 is experiencing transmission issues at lower RPMs (1500 ish) when the throttle is only slightly open. It feels like I am driving over small rumble strips. The shifting is also not smooth and kind of "clunky" at slower acceleration. Anyone else experiencing this and if so what did you do to fix it? Thank you!!
Update, there is a TSB regarding my tranny issue. If you are still within the powertrain it will get fixed for free. They used the incorrect Trans fluid in the 2019's. Mine was put of warranty but GMC covered 30%. Better than nothing. So far my vibration issue is gone.
 

I can't believe this is still a thing. I would have thought GM learned their lesson years ago. My '16 SLT with the 8 spd transmission had the same issue. They used the incorrect fluid so the fix was to flush the transmission (multiple times if needed) and refill with different fluid.
FWIW, that fix lasted 4 or 5 years and now the clunky shift from 1st to 2nd is back. I'm not bothering with it as I'm looking to trade in on a '24 AT4.
Good luck guys!
 

Update, there is a TSB regarding my tranny issue. If you are still within the powertrain it will get fixed for free. They used the incorrect Trans fluid in the 2019's. Mine was put of warranty but GMC covered 30%. Better than nothing. So far my vibration issue is gone.
Which transmission fluid is the correct one to use now?

I’m at 83,500 on the OD and my truck just started with the rumble strips feeling. Only happens when I’m on the freeway and light throttle, so damn annoying it feels like it’s going to breakdown.

Funny enough, when towing my 9k LB toy hauler, the transmission is smooth as butter.
 

For anyone experiencing the notorious "rumble strip" at highway speeds, I replaced the trans fluid this past weekend with Dextron ULV and a new trans fluid filter and it completely resolved the issue. There is a DIY now on youtube and only took me about 4 hours.
 

I have a 19 sierra 1500 AT4 and second gear shifts hard, I get a slight vibration while driving, and when I shift to reverse I get a serious clunking noise. When I am pulling my enclosed trailer in tow mode it seems to help??? Weird. Any recommendations or help?
 

I have a 19 sierra 1500 AT4 and second gear shifts hard, I get a slight vibration while driving, and when I shift to reverse I get a serious clunking noise. When I am pulling my enclosed trailer in tow mode it seems to help??? Weird. Any recommendations or help?
The fix from GM has been to replace the transmission fluid.
 

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