OK Picture this. A question comes up with the same problem you have/had. Right now the answer would be, switch the block. I don't know why, just do it. You would have said,"I'm not switching it until I know why". You are asking us to do what you would not have done. Throw parts at the problem.

I understand that you are an electrical engineer. After 4 years of engineering school you have the tools to inspect the part and tell us what happened to it. I have been through engineering school and trade school not to mention being a mechanic for 25 years and nothing that has been written makes any mechanical sense. Just tell us what happened. 'I don't know' doesn't fly well after three pages of heartfelt help and time donated to your problem. Also, you owe the future board answers now that you have reaped the help provided. Wouldn't you like to be able to provide a logical answer to a problem that you have hands on experience with? You have been down the path of the rear end diff R&R and brake R&R and many other paths. It would be great if you could help your fledgeling brothers in Birds with the their questions. Look back at these postings and concider how much time and thinking went into the answers. We actually cared that your brakes were not working. It's like a puzzle and you are running off with the last pieces.