Well I do have an unsolvable vibration at 70+, in addition to noise. I asked this question on the forum before, because I had my Torque Converter replaced, this all developed after they did this. I was assured that disconnecting the driveshaft at the transmission wouldn't have made a difference, they didn't need to index those bolts? Is that correct or incorrect, I don't want to spend all this money for no reason if the driveshaft needs to be rebalanced.
The tranny shop either lied to you, or was ignorant of the indexing of the driveshaft. As other people have said, it needs to go back in,
exactly as it came out. The carrier bearing could also still be an issue. It's not so much the bearing that goes bad, but the rubber around it deteriorates. Unfortunately, the whole thing has to be replaced. Ford part # 4A499. I belive this part was also used on some Ford trucks, so it
should still be available for around $100-$125.
If you plan on doing this yourself, the exhaust will have to be dropped. A necessary evil. Get 4 different colored paint sticks, and mark each bolt and hardware to its location on the flange. Do this for both front and rear. Also, don't forget to mark the splined section, before separating.
Since the driveshaft has already been out. You may be best off pulling the shaft, and taking it somewhere to be rebalanced as Telco said. They will need the complete assmebly,
from flange to flange. Make sure you explain the situation you are having, and that from what you understand, it has to be balanced right down to the last nut and bolt. It may take some time, (especially if the washers and collars were moved to a different location in the rubber), and cost a little extra to do it this way. If they want to just throw extra weights on it, this is just a bandaid approach, and I don't know how well it will work.
If this isn't fixed, you risk messing up your pinion bearing in the differential, and that will need a rebuild next.
Hope this works out for you.
---Mike---