The main thing is to start taking it apart when you have a few days to work on it and don't take it apart then work on it a few days later you will f@%! stuff up that way, trust me. It took me two days to rebuild my first 5 speed in my ranger, witch is very similar to the t45 and I didn't have any help or instructions. The tranny is still in my truck with around 30,xxx mile on it since I rebuilt it. Oh to let you know the truck has 230,xxx miles all together.
Oh watch out for the ball bearings for the shift linkage they have a tendency to fall out.