Was there any smoke from any point on the vehicle? I ask because the accessory drive belt may be getting damaged due to a pulley that froze, but that wouldn't cause a transmission issue. If the "high gear" could have been loss of power, the belt could be dragging causing the engine to work harder.
Let me know as much as you can. If possible, inspect the accessory drive belt (serpentine belt). Open the hood and inspect it visually, and also note if there is a smell coming from it.
Additionally, let me know if the check engine light is now on and not turning off when the engine is running
I will watch for your reply.
Tuesday, November 23rd, 2021 AT 8:14 PM