An upgraded torque/stall converter as the old one has to be unbolted from the flywheel anyway and the Sharadon Stage 2 or 3 Tranny Valve body. Any transmission shop can do it for you but its simple to replace.

Here is a really good step by step writeup by oldirtyjohn
https://dodgeforum.com/forum/3rd-gen...-tutorial.html

Here is when I did mine. It doesn't take very long.
https://dodgeforum.com/forum/3rd-gen...oem-lsd-3.html