Thought it was fixed! :o(

does it have the stock gears in it? if it does have some check them to see if they are good or not, i had the same problem with my car when it only had 23000 miles on it. took it to a friend and found out the crush collar was bad and ring gear walked into cover.

That sounds completely wrong. Take it back and make it clear that they will be fixing it back to the way it was before the accident.

Was this happening with the old rear end or your fancy new* v-6 rear end?

If they replaced your GT rearend with a V6 rearend then you got royally.....use your imagination.

One of the major differences between the V8 and V6 platforms is that the V6 uses the wimpy 7.5" rear axle. The GT uses the much better 8.8". They throw that stupid 7.5 in there because salvage units are extremely easy to come by. Then you wonder why the first thing that happens when you put any decent torque to it is the destruction of the rearend.

Check the housing and see which you have. If they did indeed replace your 8.8 with a 7.5, that punch in the head is not only well deserved, but pretty much mandatory.

Even if it is an 8.8, they didn't check for leaks and probably didn't check the fluid level either which is just plain negligent. That squealing means your internals were getting ground up. Don't put up with that. In any case, at this point, a newly remanufactured unit in not unreasonable. If you don't get satisfaction, call an attourney.

Also, I don't think that squeal is the E-brake, I think it is improperly set gear backlash. Each housing, differential, and gear set, need a shim set matched to them for proper backlash tolerance. To tight and it whines, to loose and it gets clunky grinding. If any of those components came from a different unit, they have to reset backlash using new shims, which takes a lot of time and gets fudged A LOT. Ask if they set the backlash properly, I think factory spec is between .004" and .012". They should have written down what they set it to. Don't tell them what the spec is, just check their knowledge. If they didn't set it properly, LIGHT THEM UP!

Sorry for the rant, I have family that specializes in this field (I used to myself). If we had ever pulled the stunts that those people pulled they would lose their contract with the insurance company to say the least, and we would have been sued for sure.

It sucks so bad that most Ford Dealerships are so crappy when it comes to service (and brains). Hope it all works out for you Bro.

I went through hell when I bought my 96 Cobra from the Ford Stealership.
First I threw it into a turn the first night and it 180'd (leak in the rear tire). Then I found out 2nd gear would grind on a power shift, BUT ONLY ON A POWER SHIFT.
Try and get one of those morons to simulate that it

I went back like a crazy man the first night and made them give me brand new tires all around but when they took it for a drive they would tell me the transmission was fine. And if you drove it normal it was, BUT power shift it and grind grind grind...

Finally after 3 days of screaming and yelling I walked into the SHOWROOM that first weekend and went ballistic, (I am truly surprised I wasnt arrested), I made such a scene in front of everyone in the showroom that no one knew what to do. Then FINALLY the salesman that sold me the Cobra walked up to the manager in front of me and said, he's right the tranny is bad, it was grinding for me when I took it to get detailed. He then had them overnight the parts and it was fixed the next day (and never grind again)

We became friends and I bought my first Lightning and other vehicles from him since then (we now have an understanding )