Put the car on lift and remove the tires.
Take off just the calipers and set it to the side...I didn't do the remove the spline nut thing GM recommends.
Unplug the abs sensor
Now with a 18mm socket and wrench...take out all 4 of the bushing bolts on the inside of the hub(the suspension linkage). All but 1 has just a standard bolt hole. 1 of them has a slight elongated hole for adjustments. The nut will leave a indention where it was..so put it back in the same spot when done.
Now have a helper take a pry bar and gently put it between the diff and the big round ends of the axles. At the same time you pull on the hub section,have him pry out on the axles....they just pop out. Let them just hang there. Let the hub assembly hang by the emergency cable. Do the other side.
Now for the drive shaft. I took a large wrench and slide it over the ears of the drive shaft(you'll figure it out when doing this) to keep it from turning as you take out the 3 bolts holding it on. Let it hang there.
Unhook the exhaust from the 2 hangers right behind the diff.
Reach above the diff and unplug the breather tube.
Now take out the 3 bushing bolts holding the diff. It shouldn't fall. If it does it'll rest on the exhaust. Now pull the rear down first. Then pull the front down till it just clears the mounts. Have your helper with one hand pull the exhaust down,while using the other to assist you. Now while pulling the rear down,twist the diff,so as to pull it down and thru the exhaust. It should just fit thru. For some reason...no fluid was spilt while doing this. Set the diff down...take a break....now just reverse the process and put the new in.
If you do the pedders bushings....you'll have to push the diff back in the holders real hard...there TIGHT!
Once installed you might have to take alittle of the fluid out of your old one to top off the new one. I had one of those cheap hand pumps that fit oil bottles...
I started this at 8:00am...at 10:30am I was driving down the street.
Hope this helps some....my way isn't the GM way...but it's faster...2.5 hours vs. about 7 by the book.