At this point, you may have to drive it carefully until the code resets. Since it still jumps out of gear, it should reset the code.
I wish I had an easier answer. There are many things that can cause this. Without the code, it becomes a guessing game and I don't want to have you buying parts only to not be correct. I'm sure you don't want to do that either. LOL
If you can, carefully drive it so as to not put yourself in danger and be easy on it so it doesn't cause additional damage. After that, see if the code returned.
Let me know.
Joe
Friday, September 20th, 2019 AT 9:28 PM