Hey cooper, nice write up! Welcome to the forum.
I don't have a ton of time right now, but we can get a discussion going...
Something's not making sense to me. You say you were hit on the DS but, the mechanic points to the diff as the problem? That's all the way on the other side. There would have to be some major damage to warrant a full rebuild.
"kids these days" like made me laugh. Thanks!
You want trans pictures?
http://www.grandprixforums.net/threa...ity-takes-time
Post #80 shows the diffy and cover