727 fresh rebuild. no fluid pressure

Hi guys. I just rebuilt my first 727. it was slipping in all gears i thought because the guy i bought it off ran it out of fluid. It came apart and went back together really smoothly. new steels plates bands seals filter fluid. pump looked good. . . i put the old torque converter in. it went in as it should.both shafts engaged. had to pull the torque converter forward just a bit to bolt it up to the ring gear. so i'm pretty sure the torque converter is installed properly.
I have nothing in any gear. the only sound was the click of the linkage moving. So i quickly shut it off thinking no fluid pressure confirmed by checking cooling line pressure. I took the pan off and everything looked good. but im not that familiar with the 727. what am i missing? thanks.

Well it has to be filled with fluid in neutral. It will not charge the converter in park so there will be no cooler fluid flow either as that comes from the converter. It should say that on the dipstick to check in neutral.

As already mentioned if you ran it in neutral and have no fluid movement then the pump drive tangs probably got broken off
Mopar converters can be a real bear to get them to engage the pump drive tangs properly, the converter needs to drop down on them usually three different times, unless you get real lucky
It will have right at 3/4 inch from the front of the four converter lugs to the front edge of the tranny flange when fully engaged all the way in
I stand the tranny up so I can see inside the pump so I can align the drive tangs so they are straight up and down or sideways, your choice, and then align the drive slots in the converter hub and drop it in gently and slowly turn the converter both ways so it will drop down onto the drive tangs on the pump gear properly, it will thunk when it does that
My race car has a Powerglide in it and it doesn't have these issues, it slides right in

I guess its time to pull it again.
Thank you.

I got the transmission out. the torque converter lugs are exactly like you said. 3/4 inch from the front of trany flange. is there anything else that would cause the pump drive tangs to break? I can't think of anything else that would cause no pressure. It seems like a pretty simple system. but i can't seem to figure this one out.
I'm about to pull the pump out. i really hope i find something broken. I like fixing things. its not often i put things together and they don't work. Especially when they come apart and go together as planed. but this is my first 727 rebuild. I guess im doing it the hard way. hahaha.

I have the pump pulled. the pump drive tangs are good. I hate to put it back together without finding the problem. everything looks good. it air tested perfect. could it be in the valve body? I should have pressure if it was in there?
If the torque converter was bad i should still have fluid pressure as long as its turning the pump? I put my fingers in the torque converter to check the input shaft sleeve. it seemed really loose. how much movement should there be there?

I'll defer to John & Transman but I would now think valvebody (not much left to choose from) as far as potentials.

How much fluid did you put in it? I dont see this mentioned anywhere,,,,,I always put in 6 qts then run it for a min. and add more takes about 12 qts. to be full....I think

Good question Depending on the depth of the pan I usually start with 3 or 4 then add accordingly stopping at the 1 pint mark as the fluid will expand when warm. Total capacity will vary depending on converter size etc.

If you have it apart this far I would verify the regulator valve is free and not stuck out, and check the tc valve.
If the clutches and bands pass air pressure test (use 30psi) then likely you didn’t have enough fluid or the vb is your culprit.

A stuck tc valve won’t allow the converter to fill and you won’t have cooler flow.

You should have stuck a gauge on it before you yanked it. You need converter charge and line pressure.

I decided not to be cheap. new pump. new torque converter. valve body rebuild. Im not pulling the transmission out any more to see whats wrong. it cost me less in parts than seeing a therapist. hahaha. It works great. thanks for all your advise.

Thanks for the feedback and glad it's fixed

glad it's fixed as well, although it would have been nice to know what the problem really was.