Thanks for the additional tips.
Here's where I'm stuck.
Most of the undercarriage on this looks like it was hauled up from the Titanic and the PO was not real diligent about maintenance below the beltline, so getting to the point of being ready to unbolt the TC nuts has so far been a big weekend exercise of breaker bars and PB Blaster and hoping bolts don't snap off.
However, here I am with the driveshafts out, the shifter cable disconnected, the shifter bracket unbolted, the crossmember dropped a couple inches, an time to remove the TC nuts.
I started first with the one on the bottom but there is a big bracket bolted to the bottom of the trans that is in the way. I've got 1/4 , 3/8 ratchets, short and deep sockets, flex-head gear wrenches, swivels, etc. and I can get the 1/4 ratchet with the deep socket over the head of the nut but cranking on that with the little bit of room that is in there it will not budge.
I can see if I dropped the bracket off the trans I could get to it to put a breaker bar on it but I just don't see how you folks get these frozen nuts off with no room to work. maybe I just need to go buy a set of box end wrenches with right-angle heads or crows-foot wrenches that you all have because I'm just not seeing how to do it. But thanks for all the tips.