Rick,
My guess is that one of the shifter arms got knocked out of the 'gate', and you really aren't getting a true side to side swing through that gate.
Could you crawl under the truck and manually shift all the arms back to a neutral, then try it again. If the disc was stuck to the flywheel, depressing the clutch wouldn't release anything and you would still not be able to move the rig.
It has to be the transmission, and the chances of a whacked out of position shift arm are pretty darn good...I hope!
Stuart
