I’m having an issue with my 727 torqueflite and I need some help from you geniuses. I’ll start with some details:
My 727 was rebuilt by me a number of years back with nothing too spectacular thrown in. I put some red bands in, an A&A 5400 RPM governor, B&M deep cast aluminum pan and an external tube and fin cooler. It’s always run excellent and I’ve never had issues with it. Then I put a 493 stroker in (my car is a 1969 Plymouth Satellite) and added a 2800 stall converter. It has still been rock solid. I then added a temperature sender in the pan which I know now is pretty much worthless. That temp gauge never even moved.

So recently I reprogrammed my valve body with a Transgo TF-2 kit and it ran even better. The shifts were amazing. Shortly after I started getting a whine from the front of the trans (bellhousing area). It would only whine in drive gears, not in park or neutral. After a few weeks the whine suddenly went away. Then I drove up the canyon and the temp gauge that never moves suddenly starts climbing. Way up above engine operating temp. No amount of downhill easy driving would cool it down. All I could do is shut it down and let it cool. This happens every time I drive it. I then realized that even when the trans temp was at almost 250 degrees the cooler lines were cold. There’s no fluid pumping through the cooler.

So I just swapped out the valve body for a stock one to see if maybe I messed the other one up. Same problem. It runs solid, no slipping or erratic shifting but that temp just climbs and the cooler lines are cold. When I had the valve body out this time I blew out the lines and also the channel in the trans with compressed air. There is definitely not a blockage.

So what is preventing fluid from being pumped to the cooler and making the trans overheat? Could the trans still run rock solid with a bad pump? I’m at a loss. Any help would be appreciated.

This was the color of the ATF by the way. I know it can't be good...

Short answer, NO.
No pump pressure = no gears

Put a pressure gauge on the line port. my money it goes sky high pressure wise
If the trans is hot (and works) and the lines are cold theres a blockage

That's what I thought because an automatic transmission is basically a hydraulic pump but I just wanted to make sure I wasn't missing something.

Just to make sure we're on the same page, you're saying remove the cooler line from the front port and screw a gauge directly into the port, right?

remove the rear line and add a hose to run it into a 5 gal bucket .

start engine with trans in N if you have a good fluid flow here there is no blockage and pump is working .

you may have a bad sending unit for the gauge !

use a temp gun to see actual trans temp when gauge says hot !

Where did you check the cooler flow? The front port exits the trans directly from the converter. The rear line is the return into the trans. No fluid at the rear line could be a plugged cooler or line. No fluid out the front port of the trans after swapping valve body's is puzzling. The only thing I can think of is a restriction in the pump discharge passage.
Doug

looking at the color of that fluid I think it's safe to say the sending unit is not the culprit. interesting that it shifts ok, but cooler lines are "cold". Shifting ok would indicate pump is "ok", but the cooler line scenario says differently. Can't wait to hear the results of starting in up in N with the return cooler line in a bucket.

No, the line pressure test port is on pass side. Pressure should be 'about' 75 psi at idle , and should rise as the kick down lever is moved rearward.

But looking at your fluid condition. I would say a rebuild is in its very near future. Looks like metal indicating hard part failure internally

I blew compressed air directly into the outlet port where fluid is directed from the valve body to the cooler. I even blew compressed air in the feed and return hole for the torque converter. I'm about to go out and do a few tests so I'll keep you guys posted. I'm glad I'm not the only one puzzled by this. I've been studying my Carl Munroe handbook for a while now trying to figure this out.

I just got done messing around with it. I had the cooler lines run through the radiator cooler before running through my external cooler, something I totally forgot I had done. I'm only 30 and I'm already forgetting things! It turns out the radiator cooler is blocked. Anything downstream of it had no flow. So I bypassed it and now there is full flow to the back of the transmission. I did all this by disconnecting lines and putting a 5 gallon bucket under them. When the fluid is pumping it definitely pumps! I almost filled the bucket up in less than a minute.

Anyway, thanks for the support guys. I made this way more complicated than it should have been.

Let's hope you didn't fry the clutches...The fluid isn't looking good there... Something has ground itself to get that color...I'm glad you've found the problem but it might not be over...

Whatever ate itself could be wjat plugged the cooler too.

Yeah I'm sure this is just the beginning of more chain of events. The fresh fluid I put in didn't look much better when I got it pumping out. Something got fried in there and it's only a short matter of time until it'll need a rebuild. I'm hoping the clutches took the brunt of it and not any steel parts.

Pull the pan and see whats in there. You are gonna have to do that anyway. Fluid looking like that is pretty bad.

I just had the pan off and the bottom of it was caked in metal and/or clutch material. About like the fluid.