On older fords, I've done things like blocke dthe clutch down for a few days ( sometimes this alone heals the problem ).. after blocking for a while the I've done these various things.. sometimes one works.. sometimes another works..
( I'm not sure what trans setup you have or if you have manual pto or independent pto.. but if independent.. it gets more difficult.. )
1, engage pto and start tractor with a load on the pto.. like a rotary mower.. the extra load of the mower drivetrain can unstick the clutch...this is really only an option on mechanical pto setups... not independent
2, push tractor out in the open and select a safe gear and jimmy her up so you can start her in gear from the drivers seat.. keep clutch blocked.. drive in tight figure-8's and stomp the brake on the outside wheel while in the turn.
Once you do get her to pop free.. slip the clutch a bit.. like taking off in high gear.. and remember to start blocking the clutch from now on.
good luck... this kind of stuff works commonly on N and other smaller fords with single and dual clutch setups.. never had to dink with an independent clutch job that had a sticky drivetrain clutch ( knock on wood )
soundguy