When my carrier support went out on the previous car, I had a sort of pharumping noise whenever the trans shifted at higher speeds. The rubber part of the carrier had come apart, allowing slop in that part of the shaft. It would flop with any change in rpms. Can't remember if you can see that with it on the car, but it would be worth peering up at with a light to see if its ripped open. If the driveshaft has to be dropped for any of it, I'd replace both discs, support, and carrier bearing as a preventative repair, so you'll like never have to do it again. Its on my to-do list in the next couple months with my daily driver. Make sure the car is supported off the ground and well chocked so it doesn't roll on top of you and squash you.

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1983 CD
1958 Studebaker Packard (being resuscitated)