Transmission needs replacement or rebuild

This depends solely on the cost of the unit to be installed (assuming you are not doing it yourself) versus the value of the vehicle.

I would start with going to an online appraisal website and get a value of your vehicle in good working order. Then get a few estimates on getting the unit replaced. If the cost of replacing the unit exceeds the value of the vehicle then it is not worth putting that money into it. It is always better to take the money to get it repaired, plus whatever you can get for the vehicle in its current state and buy a different vehicle.

Here is a guide that will help with replacement if you are going to do it:

https://www.youtube.com/watch?v=3vJAojsrfuU

Let me know if you have questions but it other then this, it is hard to tell you how long a vehicle will last. The only thing you can do is based your decision on what we know today. Clearly if we could see into the future we would be much better off with everything but that is not possible so we can only based on today.

Also, below you will find the process on replacing the unit. Let me know if you have questions. Thanks