Vehicle shut-off while in route, in traffic, check engine light then came on. The second time this occurred, check engine light came on and immediately vehicle proceeded decelerate from 55 mph to 25 mph while I was on a highway. The vehicle would not shift to a higher gear and remained in the lower gear at 30 mph on a 55 mph highway, causing me to move off to the side , turn off the vehicle and then restart the vehicle. Check engine light not shown, vehicle operated, except shifted hard. On several occasions I have shared with the dealer at service appointments that I experienced transmission sensor issues causing delayed shifting, not able to shift into reverse or drive from park, vehicles stalled, and rough gear changes, unusual noises coming from the transmission. The engine check light would come on, then disappear shortly after, but not always. Service appointments by a Jeep dealership resulted in them updating software, which I shared did nothing to resolve the problem, so I brought the vehicle back and asked they check the transmission fluid level and cleanliness of the fluid, and whatever else needed to be checked. I was told the transmission was completely sealed and it was fine by the dealership. It was not fine, and the vehicle stalled again, and again it while on the freeway, almost getting into and accident, the transmission locked up and would not move past 30 mph. A warning light did not appear. I brought it back to the Jeep dealership for repairs because it is not safe to drive. I am being told that the transmission is defective by the service department. I asked if they drove it and they said yes. This has been a problem I have been trying to get resolved for the last four months of 2024. I do have service records, in my glove box, and a video of the transmission flashing in reverse. Vehicle is at the dealership for assessment and repair.