Hello & Welcome,
Yes these things are kind of pain to change out. I can send you the instructions for the procedure if you would like. Just let me know.
Let me send along the instructions I have, which are a little different (but not much).
Here are the figures that go with this.
Please let me know if this helps, or if I can get you more details.
Just so you know, this job calls for about 2 hours of labor time for an experienced tech.
Please feel no pressure to accept this answer if it does not help.
I will open the question back up for other experts to try and help you, as that is about all I have at this point.
Thank you for your patience.
Do you have the front end up on jackstands or a set of car ramps?
You have removed the cooling fans, correct?
Put the radiator back - it only has to come out if you have a Seville, since you have a Deville it doesnt. The alternator will come out the bottom with the front lifted, the fans removed, the AC splash guard and the bottom access panel removed.
Once you have the bolts removed it will drop out the bottom with some turning and twisting and a little cussing.
Here are some photos of it actually dropping out the bottom with radiator still in vehicle:
BTW - you think this is a pain - wait until the starter goes - it is under the intake manifold in the engine valley.
You will not find many mechanics that are fans of this engine!