833 making odd noise in 2nd gear only

I'm with you on the rational, as Ima thinking too (watch out below!).

Since it is in sync with RPMs, but the frequency does not line up with the RPMs, I am thinking it is not gears, synchros, etc. But what would line up with the erratic synchronicity?

I wish I was as efficient pulling the box as you, it would already be out. I am assuming you are not doing any hoisting of the engine to remove the case from the bellhousing (as suggested in the Service Manual). Can it slide out simply by unbolting it from the bellhousing?

Hate to pull it if I don't have too...

PS - the noise is definitely coming from the somewhere in the immediate vicinity of the transmission, that I can tell from the Driver's seat.