Third member removal

Finally getting back to trying to figure out the clunk in the rear, which is requiring me to remove the 3rd member. Axles are removed, driveshaft out, all nuts around the all 3rd member removed except the top one, that's loose.

I've been trying to get it open enough to drain fluid and remove it but the things not budging. Some fluid is leaking around a few of the bolt holes. I tried using a jack to push up on the yoke carefully, no joy.

I've read about copper crush washers, I can see those, but can't seem to remove them as there's no lip to pry them off.

Any tips? Tried tapping a screwdriver in with a hammer, but not sure if I should be hitting it harder and trying to avoid damaging it.

Thanks.