Yarddog, I believe he's following instuctions I posted on how to tear the axle down to get the 3rd out. I told him to pull the lower plate because there are no cone washers on it. That's why I always try to remove the lower plate if I can, and take off the high steer arm later if I cannot.
Here's the deal. There's a bearing in there that the lower plate press-fits into... And its one hella-tight press fit. It's not just a plate: There's a 1.5" steel shaft going up into the knuckle. Its a TIGHT press-fit. You can see the big ass post between the plate and the knuckle in this pic:
I simply took a brass punch and BEAT the tar out of it back and forth until I could barely squeeze the tip of a tiny slot screwdriver in there, pounded the screwdriver in with a BFH... switched to a bigger screwdriver, and that allowed me to slip in a prybar on one side, then the other, and pop it out 1/16" at a time. It's not just sitting on the bottom of the axle, however.
If it will **NOT** come off, you'll have to take off the steering arm on top of the knuckle instead. Same thing - big steel shaft going down into the knuckle. But this one's nice and long: You can take off the four nuts, HIT IT AS HARD AS YOU CAN SWING with a sledge way out by the tie rod's hole... and work it loose enough to squeeze a prybar in there and pry it off.
{EDIT} If you have to take the steering arm off the top instead... and you're about to hit it... try to hit it back and forth on the front, then back and forth on the rear... and repeat but hitting it up and down, and do NOT beat on the tie rod ends connecting it to the steering system. Hit right next to them instead.
If you have and problems and you need IMMEDIATE help, my cell phone number is 901-550-1712... and I don't work on mondays - just in case it HAS to be done tomorrow or something, I thought I'd give you a tech support hotline.
EDIT AGAIN: I believe the knuckle has to be disconnected from the tie rod and drag link in order for you to be able to rotate it enough to get it off of the truck: the steering arm will prevent you from taking it off if the steering linkage is connected to it.
All I can tell you is that someone told me they were able to remove the knuckle by taking the lower plate off. When I did it, I pulled the lower plate 3/4 of the way off, and took the steering arm on top of the knucle completely off... and the knuckle came right off with a little wrestling to find the right spot to rotate it to and yank. One of the other guys I helped, had the steering disconnected and we simply took out the lower plate and left the upper steering arm tight. It was a bitch to get off, but it came off.