HELP! Clutch wont disengage!

[f350dually]

I have a 2000 f350 super duty manual transmission with about 64k miles on it and some light modifications (exhaust, intake, light chip). Earlier today i was towing my fifth wheel and pulled over and the clutch wouldn't fully disengage. I yanked it out of gear to get it to stop. I got it to shift (very roughly) and limped it home (only about 20 freeway miles). By that time, the clutch was completely engaged all the time. I had to turn the truck off to get it to stop. Is this the slave cylinder or the clutch itself? If i do need a new clutch which one would you recommend? Any suggestions would be greatly appreciated.

[greasltn]

If the clutch goes bad, you don't move. It could be the master or slave cyl. Check the truck out for any leak to lead you to the right cylinder. Don't forget that the master could leak inside the cab by the pedal.