HELP! PTO won't disengage...2000 Freightliner Century Class

Had initially the same issue yesterday in the woods with my T800 self-loader. Would not disengage after clutch in, first gear, flip off switch, back to neutral, clutch out. Shaft was still turning. Tried procedure again, thought it was good, but went to move forward and I could hear it try to start turning again. Stopped, unloaded, idled up to gravel and parked. Unhooked air supply, checked switch at dash, supplied and exhausted like normal. Until i can get back up with a catch pan and bucket of tranny fluid (PTO is mounted on the bottom of the tranny), should I start at the switch housing? Is the disengage spring inside of that? Just in for service a couple of weeks ago, and they "adjusted" my clutch, but not to my specs... different tech, obviously. Ideas?

 

Yes the cover where the air line goes is where the spring is. When you remove the cover it will drain the transmission oil so have a bucket ready. When you say unhooked air supply, do you mean you unhooked the air line at the pto? If not I would try that first and see if it disengages.