Driveline Screech ???

[fatboy63k10]

63 Chev k10 454,400Turbo,12-bolt 3.73 posi

I am in the "sorting out" stage of a 2 year project. On my first trips around the block, I have 2 driveline noises.
1. a "screech" that takes place under acceleration and at times when I start it up cold and in park. (but will go away when I "goose it" in park, but comes back as soon as I drive up a grade or accelerate hard.)
2. a "whine" that takes place under load whether it be acceleration or deceleration and is constant almost from start to stop. (but will stop when I let off the accelerator and put in neutral)

I have personally rebuilt the rear, and double checked the gear pattern, it is right on.
This week I rebuilt the transfer case with all new bearings, bushings and have correct tolerances and end play.
I pulled the trans today, the flexplate has no cracks, my drain pan has clean fluid, and so far have disassembled the front pump and forward clutch assy and everything is sanitary/new.
The driveshafts have new u-joints and have been balanced.

Could I have a bad rear main/thrust bearing? I checked end play with an indicator and the crank moves back and forth about .010.
Could the torque convertor be bad?
Any ideas?

I am about ready to start a very large bonfire...