So, I am taking apart another transmission, this one was complete. A 71-72 440 HP This one being a 72 model assembled 28Mar72. Not sure of it's history, but it was bound up. After removing VB, could not get park rod out and nothing would turn. Had to unclip rod from VB.

I removed the oil pump housing and immediately everything freed up and rotated at input and output.
Will say this trans is immaculate inside, all the parts seem original to the trans and have casting numbers Feb72 and in some case 3rd week of Mar72 casting dates which I found interesting. Additionally it had a 8 thousand assembled number. Which I can't believe is in a day, unless that is what they did.

So after I started looking closer at the pump and front drum, I found that it had a mismatch. The narrow bushing RSS, and a wide bushing front drum. Hence the no thrust and locked up drive train. So I examined what the drum looks like placed on that reaction shaft. You can see the gap well greater then what the fiber washer thickness would be. So I scratched my head how the oil pump even fully seated? Well some of the oil housing bolts show signs of stress on the threads. Then as I looked closer at the bushing of the front drum, it was being pressed out of the drum by the tightening of the oil pump housing. About a 1/16+".

So at some point the oil pump was swapped and caused this issue. Bands, clutches, springs all pristine, even ink stamp inspection numbers and such are still present, including the oil pump housing. The narrow band RSS has a ring ridge that sits higher up then a wide bushing support. It contacts the bushing and prevents a narrow reaction shaft from fully inserting into the front drum. Because it is much different the pump housing can not fully seat. If you do seat the pump housing, that ridge presses the bushing out while binding the drive train eliminating any thrust clearance. Pictures below.

Welcome to the world of inexperienced transmission “assemblers”.

True, but lack of mechanical and critical thinking skills too. When something is not assembling correctly, you should... stop an figure out why. What did I just change that could prevents this from working? And why was the new pump so hard to get on.

Looks like somebody wanted the wide bushing RSS and pump; and they just stuck the older narrow RSS/pump in that "donor" trans and got rid of it.
Obviously it was never put in service after the transplant.

But this is a nice HP trans with 4 pin planets, all new parts internally, and does not look worn. Lot of good stuff behind that pump. I have it all disassembled and cleaned except the main case. Already pressed bushing in. Have a wide band RSS. Going to start reassembly. I think this must have been a C body trans. Newark Vin, and studs on the tail shaft.

Must have happened in the 80's before computers were invented...

Even us limeys know about post 71 wide drums...

Twice as many post 71 727 trans as pre 71's?
66-70 and 71-78 ish...

Who would use a pre 71 transmission anyways???