I read where you can test a salvaged Duty C by energizing it and if it clunks into place then it is working. Along with the oil ports are open/closed etc...
I might go down and pull out a junker extension housing just to practice. If it comes down to me ruinig something or figuring I dont want to work on it, thwn I am only out thew $1 it costs to get in. Better to practice on a junker than ruin your own vehcile eh?
How difficult is it to replace the clutch plates while your in there?
Any special tools?
Any new gaskets/seals needed?
I assume I will need header gaskets too if those need to come off? maybe just remove from Cat back?