Good call on soaking it in lube.
Do that overnight, then here's the trick. Put the pipe-wrench on it (the biggest one you have) and use the floor jack and heat to break it loose.
Yep, a floor jack.
Granted, if your joints are not in the best of shape, this could put them over the edge. But if they're still good, you can literally lift the truck up off the ground with the wrench on the bar.
If that's not enough, use some heat from a propane torch.
Doing this does not need to be way off the ground. Obviously, just as you start to put some up-english on it, you've got plenty of weight on things. It's a little nerve-wracking, but it should work.
If that doesn't do it, jump up on the bumper. I stopped being worried about breaking something since I figured that, if it was this bad, I'd probably need to replace the darn things anyway. Luckily, I didn't have to.
On the third bounce, mine let go with a loud bang, and has worked fine ever since.
Paul