Download the manual from Tremec
http://www.ttcautomotive.com/English...ice_Manual.pdf
The file is 70 ish pages, so it will take some time to download.
Removing the tailshaft and Cover/forks is easy enough, and the Reverse / 5th fork/rod is part of the same mechanisim, so something is probably wrong there. That whole mechanism is sorta seperate from all the gears etc so it can be fixed with normal tools