Hi, I am John Mc, a Ford dealer tech. I hope I can help you quickly and accurately. One moment while I work on your problem.
It sounds like you may have some internal problems. If you had noise in the transmission chances are your reverse/hi drum may be damaged. You could have damaged clutches in that drum or damaged hydraulic seals. Doubt you need an entire new transmission, I would suggest taking to a transmission shop and if needed have the unit overhauled. It will be about half the price of replacement and if done by a reputable shop will be just as reliable.
If it is shifting fine in all the gears except reverse there are two possibilities. You could either have a broken reverse band or you could have an issue with your solenoid pack. I doubt you have a solenoid pack problem because if you did your od light would be flashing and you wouldn't have had any noise in the transmission. The noise in the transmission is what gives me the idea that it is definately internal damage.
Ok, your next step needs to be getting it scanned to see what codes you have. If you have solenoid codes then you replace the solenoid pack first. If you still have a problem after chances are the solennoid pack going bad caused damage to other internal parts.
But still, the noise is never good with an automatic.
Yes, this transmission isn't too bad, most shops should be able to easily handle it.
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