You have to pull the pull the tail housing to get that pin out , if YOU think you might have a leak back there do it and replace the o ring on the shaft , put in 2 if the shaft has 2 grooves abd use RTV , otherwise you should be able to loosen the adjuster all the way and get the piston out . It's been some time that I did one of these to a trans that wasn't apart on my bench so I may be wrong, but the TF-2 instructions are centered on modifying a trans that is still installed in the car.