Great day
Wondering how much of a job it is replacing a roll pin which holds the line from the master in place?
Tight to get in there with anything, maybe a pry bar to push it in???
I figure the trans has to come out! ugh

 

Helps to know make/model/year and stuff, but if you're talking about the pin that disconnects the pressure line, I cut the head off a tiny finish nail and used wide jaw channel locks to press it through . You shouldn't need to disconnect that to get the trans out thought, just to replace the master-slave hydraulic line. The line disconnects at the trans with a special tool or a couple flat heads or picks to depress the cuff and slide it out.