Need to change the PTO shaft on a shredder but I cannot get the old one off the gearbox. It has moved maybe a half inch from being completely stuck on but now it won't budge. I started with a come-a-long and a chain through the yoke then chained the shredder to a tree and attached a chain to the tractor and got it to move but it hung up. Tractor started to dig into the ground with all four wheels. Then I picked the shredder up by the shaft with my FEL...nothing. Hooked shredder back to the tractor and ran a chain from the shaft, under the tractor to the grapple and tried opening the grapple, lifting the loader, again hasn't moved. It's been hit with PB Blaster and Kroil. Also heated with a torch. I'm about to liquefy it unless y'all have any bright ideas.

chain to pick up and then torch

Fire was my first thought.

Or acetone and transmission fluid mixed together 50/50. Great penetrating fluid.

Air hammer might work

If you heat the coupling and cool the shaft it will come apart with a big hammer.

I had a stuck PTO shaft that might not have been as bad off as yours, but soaking it in various penetrating oils for a week or 10 days loosened it up. Beating on it with a small maul helped a bit.

I am assuming you can’t hook it up and engage the pto to see if it might break something loose?

I would put tension on it with your come along, tractor, whatever and then heat it up with a rosebud until it is glowing red. It will move. If need be help it along with a hammer while it is under tension and hot.

Yup.

And I've had a part that would only move when orange. Lose color and it would stick again.

Yup.

Angle grinder w/metal cut-off wheel will make quick work of that outer yellow part - except if you need to save that part.

Do this right and I bet you can tap it off.

Looks a little rusty/pitted. I would be hooking up to the pto and spin it on lower rpms and slowly pull away without getting all the way out of course to prevent the shaft from flailing all over the place. May have to chain the shredder to something if really stuck.
I had one that part of the shear pin got caught in there and it was a bear to get released.

Not an option. I'm replacing it because the quick connect on the tractor side chit the bed; both yokes are bent and the u-joint sheared. The replacement parts are $180 vs $400 for a new assemble and the shaft has given me issues because of the corrosion. I have had to disassemble the two piece shaft and hit it with a wire wheel and grease it a couple times just to get it to slide easily. I'm don't with it. Taking a Metabo to it when I get home.

May try blocking the blade and a pipe wrench on the old shaft.

Heat and remove. Done!

NAPA sells Kroil. One of the top rated penetrants out there. The power plants that I worked at for 30 years used it almost exclusively

BFH. If that doesn’t work get a bigger FH.

There is a bottle of Kroil in the picture in the OP.

Not to be missed in this discussion is the value in applying anti-seize grease before re-attaching the new shaft. I'm old enough to remember when it was trademarked as "Never Seize" and there seemed to be just one manufacturer of the stuff. Now you can find it on the shelf in just about any auto parts store having been made by any number of manufacturers. I just hope the guy who originally thought of mixing small metal fragments with grease was the one who made a fortune off his invention.

Did you get it out?

Id be careful with heat. I have roasted a few seals trying to do it that way. Let me ask this: Is there enough room to push the yoke further on the shaft, and is there enough room to get a die grinder onto the outer edge of the shaft to grind a little bevel on it?

Also try putting the come-along back on it. Pull pressure on it while tapping the shaft with a hammer.

Go to the 1:19 mark which is past the WD 40's, I have been seeing a lot of ads for Quick PTO Link/coupling hook ups anybody use one?

Heat, tension witht the chain ran under the tractor to the grapple and a BFH. Took several dozen blows and lots of Kroil.