Can anyone tell me how to remove the output shaft from a c6.

Reomove everything from the case (from the pump side) when you get to the second to the last piece remove the snap ring & pull the shaft out :flipoff2:

seriously, the shaft is one of the pieces to come out of a c-6 (unless it is a bolt on yoke c-6)

Do I need any special tools to pull the tranny apart.

Is the tranny in good condition? are you going to rebuild it while it is apart?

If all you want to do is replace the output shaft, then no special tools are required, however a set of flat nose snap ring pliers will make life much easier to remove that last snap ring,

that last snap ring can be a mothfukle.... but the rest is very easy to do. I can have mine torn apart in about 20 min.