POWER TRAIN,ENGINEWhile driving a 2023 Acura Integra with a manual transmission, and when performing a three-point turn on a residential street with a 25 MPH speed limit, I noticed the manual gearbox shifter was very stiff and difficult to shift the vehicle into a gear, despite having the clutch pedal pressed completely down. No warning lights, messages or other alerts were displayed on the dashboard. No other vehicle symptoms were noted prior to this incident. This incident posed a potential safety risk, as the vehicle was stuck in the middle of the road in direct line of traffic and needed to be pushed out of the road to avoid potential collision with other moving vehicles. The vehicle was inspected by both a dealership and the manufacturer, who both stated based on a computer scan of the vehicle, which revealed Engine Code P0219 Engine Over-Speed Condition, caused physical damage to the transmission as a result of an improper downshift. Details indicated the car was allegedly downshifted improperly at a speed of 67 MPH with an RPM of 5,551. I am unsure how this issue could have happened, as I have never abused the transmission, and have always driven the car in a responsible manner in which it is intended to be driven. The vehicle has always been serviced by an Acura dealership and have never had any prior issues. The vehicle is also still new and under warranty, however I was told they will not be covering this incident under warranty as they claim there was alleged physical damage. Neither the dealership nor the manufacturer could provide me with a time stamp or other data to substantiate their claim of physical damage, so I am unable to isolate the alleged incident to a specific date or time of occurrence. I do not see any open recalls relating to the transmission or gearbox, however I do see one open recall (VJV 2023-25) which says the steering gearbox worm wheel may have been manufactured incorrectly, which can cause the wheel to swell when hot or damp. Please investigate.