dtownsend,
Gentle taps usually don't cut it in this operation. We often wind up with the whole thing in our twenty ton shop press AND apply heat, AND belt the heck out of the thing. Usually, when one finally goes, it goes with a BANG!!! And, this is in Colorado, where rust is illegal...
Keep trying. If no luck, take it to a shop, but don't destroy that top trunnion. They are no longer available new. We need to preserve all the stuff we can.
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon