All your symptoms sure do point to a $35 bearing as RRPhil pointed out early in this discussion. Happened to me a couple years ago. I fixed it myself, and it's an easy fix if all the slam-banging hasn't caused additional issues for you by now. Every time you rev then get the slam, you've been slipping that "A" clutch. The entire rebuild kit with o-rings and friction plates is only a few hundred bucks.

So while they have this thing out, make certain the shaft end play is well within spec.

I may have missed something critical in this thread, but I thought I read that this was supposedly rebuilt? Might want to consider that whatever was done did not rise to a "rebuild" in the sense most of us think of.