I literally just finished taking my disconnect off my 08 envoy tonight...the third night of working on it, haha. I can say it is not an easy task. Mine was stuck in there pretty good. I tapped on the top of it with a small hammer (not much room), and got underneath (might have to take a skid plate off, mine is gone lol) and noticed a place to wedge a large flat head screwdriver from below. Pounded on this with big hammer enough to get a tiny gap between mounting bolt holes and the oil pan. This is where I should have got out and tapped it back into place before continuing I think. Anyways I worked between tapping it from the side with a hammer and trying to wedge from below. This was a fairly difficult process but. I finally achieve a small enough gap in the top/front mounting hole to begin hammering a screwdriver/wedge in there (Hope i didn't ruin the mounting surface too much and it hold good when done). Working back and forth between every place to hammer a wedge into for awhile, the darned thing finally fell out. Hooray! not. I then realized I had broke it off, leaving the part stuck inside the oil pan. This is why I say I should have tapped it back in before continuing. I let it bind in there, when I should have backed it off and just worked it around to loosen some corrosion before prying/wedging too hard. Hopefully this info will help prevent you from the same horrible mistake I made (who knows if I could have got mine out without breaking it anyways though..).
Anywho, I then went in and drilled holes all the way through the casing. Had to be careful not to ruin the shaft/outside bore of the oil pan. However drilling straight in from the side, you don't have to worry too much about going too far, because the drill catches when you hit the end of the aluminum casing, and then if you keep going the seal will stop you from drilling into the oil pan. I drilled some holes, got a bigger and bigger bit until I was as close as possible to the oil pan/shaft without hurting it. Then I used a die grinder to grind as much of the casing away as possible (again, very carefully). Finally I had it mostly all ground away. Then I did the same thing about an inch away in the casing. Then I was able to hammer my screwdriver from underneath, on the lip of broken aluminum, to break a chunk of it out. Then I was able to move it around, and with a second chunk out I got it loose enough to grab with my hand and pull out. Success.
I really hope you don't have the trouble I did, and like I said if you get the bottom to move out, hit it back in before trying again to loosen it up, and hopefully it will wiggle free eventually. If not, you now have some insight/pointers at least. This sight has helped me fix a ton of things on this thing in the two months I've had it (reminds me why I'm a Ford guy, hehe
). Without it I would still be lost in frustration (still am a little obviously lol).