727 Help Please

-
oldkimmer said:
Those pump gears look pretty bad in my poinion. Is this after they were cleaned up? It could possibly be the converter valve in the valve body is in backwards or the manual valve is misadjusted. With next to no atf in the converter it sure sounds like the pump. Kim
Click to expand...
Thank you Kim. The V/B was sent back to Turbo Action for inspection. And a pump in better condition was sourced. looking at the 727 rebuild book I'm unable to locate an end play measurement for the planetary stack. Is there a spec that should be inspected, before the unit is reassembled? The flow diagram seems to indicate that the output shaft is charged through the front planetary and through the governor valve. Don't want to miss anything.
 
Illahe said:
Thank you Kim. The V/B was sent back to Turbo Action for inspection. And a pump in better condition was sourced. looking at the 727 rebuild book I'm unable to locate an end play measurement for the planetary stack. Is there a spec that should be inspected, before the unit is reassembled? The flow diagram seems to indicate that the output shaft is charged through the front planetary and through the governor valve. Don't want to miss anything.
Click to expand...

The rebuild book should provide geartrain end play spec. Gear train end play is the distance between the front planetary and the snap ring on the output shaft, which holds the geartrain in place on the output shaft. I use .015-.018 spec for thrust washer geartrain. For Torrington bearing geartrain I use .010-.015. But again, reference your book. The snap ring is selective to adjust gear train end play.

The front pump to drum end play is also a selective washer, which I would tighten up from .060. As long as you are measuring end play with a dial indicator and weight on the output shaft, or ensuring the output shaft is being held stationary. If you are checking pump to drum end play without the output shaft being held stationary, you are actually measuring “free play” which is different. So how you are checking and measuring end play is very important.
 
Illahe said:
Thank you Kim. The V/B was sent back to Turbo Action for inspection. And a pump in better condition was sourced. looking at the 727 rebuild book I'm unable to locate an end play measurement for the planetary stack. Is there a spec that should be inspected, before the unit is reassembled? The flow diagram seems to indicate that the output shaft is charged through the front planetary and through the governor valve. Don't want to miss anything.
Click to expand...
Here are some pics. The alternate pump body and gears are out of a 75~ or later unit. Additionally I have a narrow bushing stator support and input shaft as an alternate, or a 77 combination stator/pump and input shaft. Stator Support and Input shaft pics are from the new build that had issues.
1721957522218.png
1721957541941.png
1721957558087.png
1721957574943.png
 
Illahe said:
Thank you Kim. The V/B was sent back to Turbo Action for inspection. And a pump in better condition was sourced. looking at the 727 rebuild book I'm unable to locate an end play measurement for the planetary stack. Is there a spec that should be inspected, before the unit is reassembled? The flow diagram seems to indicate that the output shaft is charged through the front planetary and through the governor valve. Don't want to miss anything.
Click to expand...
Forgot to add, the valve body that was built by Turbo action may have been a post 75-77 unit if that matters.

Thanks for the help.
 
Sometimes it takes a while to "bleed out valve body, I rebuild my own and run them on a test stand with gauges on it and some are stubborn three or four cycles are not always enough. Continue to cycle and add fluid as needed
 
69b7bbgts said:
Sometimes it takes a while to "bleed out valve body, I rebuild my own and run them on a test stand with gauges on it and some are stubborn three or four cycles are not always enough. Continue to cycle and add fluid as needed
Click to expand...
Thank you.
 
71Demon528 said:
With the fluid being over full while the car was running, after you lost movement, that tells me you lost pressure and fluid was no longer being pushed through the transmission. Whether it be from the front pump, the converter, or an internal part in the transmission failed causing no movement. Something quit functioning properly.

You’re to the point where I would completely disassemble the transmission, inspect every component with a fine tooth comb, and if all checks out, re assemble. If everything checks out, I would get the converter swapped out, even if you have a loaner, just to see if that fixes the issue.

If the stator in the converter fails, which is the fluid coupling device in the converter that multiplies the torque, I believe you would lose movement. Especially after doing a stall speed test, which is hard on stators.

I am to the point of spit balling because if someone came to me with this problem and the transmission checked out, I would be looking at the converter as the failure point.

Kim, thoughts?
Click to expand...
71 Demon 528:
The valve body is back at Turbo action for inspection. The pump has been swapped out with a set that has a tighter thrust clearance. .0026~ and the clutch assemblies and stator support are at the local builder to verify clearance and function. (they are air checking okay for me) but, I'm on my first build.

The geartrain clearance seems on the loose side .028~ so I have ordered the Sonnax thrust washer shim kit @.010. My question to the builders is the geartrain clearance. The Tom Hand manual has the geartrain clearance listed from .010-.020 and down to .009. Any recommendations appreciated along with the input shaft end play that is preferred.

Thanks.
 
Illahe said:
71 Demon 528:
The valve body is back at Turbo action for inspection. The pump has been swapped out with a set that has a tighter thrust clearance. .0026~ and the clutch assemblies and stator support are at the local builder to verify clearance and function. (they are air checking okay for me) but, I'm on my first build.

The geartrain clearance seems on the loose side .028~ so I have ordered the Sonnax thrust washer shim kit @.010. My question to the builders is the geartrain clearance. The Tom Hand manual has the geartrain clearance listed from .010-.020 and down to .009. Any recommendations appreciated along with the input shaft end play that is preferred.

Thanks.
Click to expand...

I’d follow the Tom Hand book on geartrain clearance. With thrust washers I’d try to stay on the .015-.020 side, but you can’t always get it 100% where you want it, hence why there’s a range.

Front pump to front drum end play id shoot for .015.
 
I wanted to thank everyone who contributed to the trouble shooting of my 727 build. The transmission was disassembled and the gear Pac lash was tightened up along with the input shaft end play. A different pump with less endplay was installed and we are on our way. One thing that cropped up was the transmission cooler is draining back and giving a false "over-full" when the car is shut down.

Cheers.
 
Illahe said:
I wanted to thank everyone who contributed to the trouble shooting of my 727 build. The transmission was disassembled and the gear Pac lash was tightened up along with the input shaft end play. A different pump with less endplay was installed and we are on our way. One thing that cropped up was the transmission cooler is draining back and giving a false "over-full" when the car is shut down.

Cheers.
Click to expand...
You’ll get “overfull” indication from cooler&converter drainback. Only time to worry about correct level is when running & in neutral.
 
68Bee said:
You’ll get “overfull” indication from cooler&converter drainback. Only time to worry about correct level is when running & in neutral.
Click to expand...
Are An check valves acceptable in the cooling lines?
 
71Demon528 said:
I wouldn’t go that route personally.
Click to expand...
Thank you for your input. I was concerned about starving the circulation, yet looking for a solution to the drain back. The cooler is mounted behind the nose of the car about 2/3 of the way up the radiator.
 
Illahe said:
Thank you for your input. I was concerned about starving the circulation, yet looking for a solution to the drain back. The cooler is mounted behind the nose of the car about 2/3 of the way up the radiator.
Click to expand...

I wouldn’t worry so much about converter drainback. It’s just the nature of the beast. I’d be more worried about a valve failing, and like you said, starving the trans of fluid. That’s a bigger problem than drainback from sitting.
 
My cooler is about same spot, haven’t worried about it for years. Start car, put in neutral for a couple seconds, then do your thing.
 
Start it in neutral, it will fill the converter. Park will not fill the converter.
 
You must log in or register to reply here.
-

Back
Top