Thanks for the information!

Is the 20 tooth rotor a '55 part in the '56 housing, or were early '56's also 20 tooth?
Doesn't the '56 housing inject the clutch oil in the center end of the pump vs. the bell housing channel, in effect getting it to where it needs to go down the converter shaft? But then with the unnecessary drilled annular holes and/or the 20 tooth rotor is the clutch oil bleeding off where it isn't supposed to go?
Not sure I fully understand the path but I don't understand why a '56 housing wouldn't work. I guess I need to know what combination is best.

As for end play on the center shaft, by hand I don't feel any at all. It's tight. As I've mentioned this trans was reportedly entirely rebuilt but that's when the clutch quit working, but everything else works fine. I don't know what, if any, problems it had beforehand.

I drilled out the broken off cooler fitting and removed the oil tubes. Here are some pictures of the pump and bell housing. The issue is no direct drive clutch actuation though the test port pressure is within range. The converter shaft has the holes in the annular groove.

Any problems seen with mismatched parts? I notice the converter shaft is the upgraded 40 tooth but the pump rotor is 20.

https://photos.app.goo.gl/5gtyR5dEyVafeFpk7

Interesting. So the deletion of the orifice doesn't cause any pressure issues in the transmission?

I see that the upper fitting for the oil cooler lines on the transmission is a special orifice fitting. Unfortunately, mine broke and had to be destroyed to remove the stub. Does anyone happen to know what the orifice size is? I assume I can pick one up at a hydraulic shop, unless someone knows a better source.

The service bulletin illustrates the original '55 front pump assembly with the clutch port on the face, and the revised '56 pump assembly with the clutch port internal to the pump into the shaft area. What isn't shown is the intermediate service replacement pump that required the holes be drilled into the converter shaft. It has a different part number per the bulletin but no description or picture. How is that pump different from the original '55 part? (The rotors are separate.)

Am still left with a mystery as to why the direct drive doesn't work when everything so far seems to check out. I wish there were an Ultramatic expert in my locale.

Nice video. Need more of those.

Looking down the inside of the reactor shaft aside from the splines for the center shaft all other surfaces appear smooth, including the bronze colored one.
There is no sideways play on the reactor shaft at all.

The old friction plate surface is hard. My fingernail doesn't dent it. As mentioned previously there's a new plate in there now but I'm not at all confident that will resolve the issue. As an aside, the case halves have a pliable O-ring seal, which is still round. The converter hasn't leaked.

The one way clutch can be felt.

Here's a thought.

The guy I bought this car from conveyed his belief that the reason for the lack of lockup was that he used the original friction plate due to it's lack of wear, and so had purchased a new one but hadn't got around to installing it.

I assume the new rebuild clutch packs installed in the transmission used friction material that differed from original, to be compatible with more modern low friction hydraulic fluid. Could it simply be that the original direct drive clutch friction plate with modern fluid would slip so badly that the driver would not feel any engagement whatsoever? I've been assuming all along that one would feel something, but maybe not. Thoughts?

Good suggestion. With a rubber tipped air nozzle on the test port, air flows freely. There's no pressurization. It feels like there's air coming out the front of the transmission but it's slight.

So the current situation is no direct drive clutch actuation in normal operation, the 40 tooth setup has the drilled holes. The clutch itself appears fine. Hydraulics on the test port indicate normal pressure at the right time when going down the road. Now there appears to be a clear path to the converter. What else could be causing the problem?

If I slipped the torque converter onto the transmission and put air at the test port, should I be able to feel the clutch actuate, perhaps in how the converter spins? I imagine the air pressure would want to push the converter off the transmission.

Looking at the front of the transmission, the bushing aft of the seal between the splines has holes in it. Are those the oil path for clutch via the annular groove drilled holes in the torque converter shaft and are they indicative of whether or not an appropriate pump is installed for the drilled 40 tooth torque converter shaft or does the bell housing have to be removed?