Just a reminder of the original complaint. 3.2 Auto - Up at Joffs place in Swindon, the box was making an awful thud when coming off the gas from high revs, enough to make me think the gearbox was going to come through the transmission tunnel into the car

Then when I got about a mile from home, I lost at least 80% of the drive. Very high revs from a standing start would just get it rolling. So I limped it the last couple of streets home where it's been parked since. Awful, awful 'tapping' noise from either GB or bellhousing area, can't tell which.
I now have the old girl nicely raised up, ready for dragging out the tranny over this weekend, oo er. I have sourced a replacement AR35 so that's no problem - but I have questions over whether or not my torque converter will also be OK.
There is LOTS of ATF all over the underside of the box. I have no idea how that's got there, as I can't see any issues with the sumps sealing, or any other oil unions. It doesn't appear to be running out anywhere. Essentially I think the box might have emptied itself!
In any case I don't trust the box (had mis-meshing before) so the known good one is going on there.
But I'm wondering if also the TC is goosed. There appears to be noise from that area - and I wonder if it was in fact the TC causing it to lose drive. There was a loud "whirring" noise when revving it in gear, when it lost drive, I can't decide whether this would have come from the box or the TC.
Is there any way to "Test" the TC or obvious signs it's failed?
I am fully conversant with the procedure for Omega gearbox swaps, no problems there, but not particularly clued up on the internals..
Thoughts.... TC, or box?

PS - yes, the MV6 is staying an Auto, certainly for time being. I have something else on my drive (that runs on that funny tractor fuel) that is much more in need of a manual shift!!!