Good to here you got it in. I was about to call this torque tube, the torque tube from hell.
That pipe you made-up to pound in the Okie the last 1/4" was a good idea.
Now you can reassemble everything.
Here is my Okie Bushing Driver Tool > Concept
I posted awhile back.
Did you turn the rear wheels to see if the propeller shaft rotates freely.
Is the wiggle gone in the propeller shaft?
Looking down torque tube, can you see if the rear Okie bronze bushing is in its original position?
Does your screw on retainer cap have to big O-ring washers?
Do you know how to correctly adjust the ball housing?
Squirt some gear lube inside the Okie before you slide in the rear yoke.
After you have it all closed up unscrew the speedometer driven gear and fill the housing with a 1/2 pint of gear lube then top-off tranny.
It takes awhile for the tranny to funnel gear lube past the main output shaft's rear bearing into the ball housing area & then to the torque tube bushings.
Run the truck for a couple miles then check tranny fluid again, keep checking until the fluid level doesn't go down any more.
Almost time to give the truck a drive!