Transmission replacement instructions please?

We need to start with checking the transmission fluid. Depending on what you find we can go in a different direction but I suspect you are going to need to replace the transmission. These vehicle have what is called a 41TE transmission and this is a pretty common issue. Basically the pump inside the unit is not able to build the pressure and it doesn't move.

Here is a guide that will help with replacing the unit but let's start with the fluid condition and go from there:

https://youtu.be/3vJAojsrfuU

Below is the process from the manual on how to check the fluid and replace the unit if you need it. Thanks