Late to this post. However, I had this issue last year on a 2020 AT4 3.0L 1500.
First time was a quick lock-up and release, wasn't sure what happened. Progressively got worse (worst was when I was passing a semi on a two lane road, locked up with another oncoming semi). I took it to the dealer and they couldn't replicate the issue, as I'm leaving it happened two-three times repeatedly in front of the same car, needless to say they had some serious road rage at me because it looked as if I was brake checking them. At this point, I was determined to see if I could replicate it on command. Turns out it happened nearly every time I would slow down then step on the gas, so usually a sudden downshift to increase speed. Immediately went back to the dealer and explained how to replicate it. Mechanic came back ghost faced and said he definitely could replicate it. Turns out it was the TCM (transmission control module) though my truck never threw a fault code. Powertrain warranty covered the issue and the dealership threw in a tranny flush to make sure there weren't any shavings from the transmission seizing.
It's been 20k miles since it happened, fingers crossed this was a one time deal.
Something to note, I had zero issues until I started towing heavily. It only happened once while towing but the issue started within weeks of pulling a large camper. I was at 50k+ miles with no issues prior to that. I had towed prior to then but nothing consistent or that heavy (even though it was within specs). Could be coincidental but possibly not.
TL;DR Same locking up problem. My truck never threw any fault codes but the Transmission Control Module was the cause of the issue. Replicated by slowing down and immediately increasing speed (downshifting, passing, etc.). This was covered under the powertrain in my case.
Late to this post. However, I had this issue last year on a 2020 AT4 3.0L 1500. First time was a quick lock-up and release, wasn't sure what happened. Progressively got worse (worst was when I was passing a semi on a two lane road, locked up with another oncoming semi). I took it to the dealer and they couldn't replicate the issue, as I'm leaving it happened two-three times repeatedly in front of the same car, needless to say they had some serious road rage at me because it looked as if I was brake checking them. At this point, I was determined to see if I could replicate it on command. Turns out it happened nearly every time I would slow down then step on the gas, so usually a sudden downshift to increase speed. Immediately went back to the dealer and explained how to replicate it. Mechanic came back ghost faced and said he definitely could replicate it. Turns out it was the TCM (transmission control module) though my truck never threw a fault code. Powertrain warranty covered the issue and the dealership threw in a tranny flush to make sure there weren't any shavings from the transmission seizing. It's been 20k miles since it happened, fingers crossed this was a one time deal. Something to note, I had zero issues until I started towing heavily. It only happened once while towing but the issue started within weeks of pulling a large camper. I was at 50k+ miles with no issues prior to that. I had towed prior to then but nothing consistent or that heavy (even though it was within specs). Could be coincidental but possibly not. TL;DR Same locking up problem. My truck never threw any fault codes but the Transmission Control Module was the cause of the issue. Replicated by slowing down and immediately increasing speed (downshifting, passing, etc.). This was covered under the powertrain in my case.