Mark, how much of a job to replace this sub assy - is it bolted or spot welded in place. I suspect the corrosion will be extended on those members - I work in an acid plant attached to the mine and see this sort of thing all the time - once it starts the cancer grows quickly. Sure you are not in the same situation however I think chasing this locally is going to end in tears and frustration unfortunately. Really sorry to see this, feel for you.