Failed transmissiom fluid cooler; flush or not?

[Mrbill426]

There is always "something" right?    Well our something is an apparent leaking of the internal transmission fluid cooler in the radiator, right off that bat with a freshly rebuilt 727/340 combination just installed with cam break-in only.    Radiator was re-cored but cooler is original.  Car has not moved more than "maybe" a couple hundred feet under its own power to load and unload from a trailer.

I have taken the radiator back to the shop for a new cooler, but in the meantime what to do about the transmission? 
Has anyone dealt with this issue?  I installed the engine and transmission as a unit from below and everything is hooked up, ready to roll. I have drained the transmission, and the converter too via the plug in it.  As fresh as everything is can I flush the transmission with reasonable expectations of success?  Transmission guys speak to me.

[Dmod1974]

The binders used to bond the friction material to the steel in the bands and clutches breaks down when exposed to coolant.  It'll either be fine, or it'll fail prematurely.  No way to know for certain if/when that will happen, so I'd flush it thoroughly as many times as necessary and send it.

[Mrbill426]

I am leaning towards that attempt.  I added red Lubegard to initial fill, whether that will have any positive effect I don't know

The binders used to bond the friction material to the steel in the bands and clutches breaks down when exposed to coolant.  It'll either be fine, or it'll fail prematurely.  No way to know for certain if/when that will happen, so I'd flush it thoroughly as many times as necessary and send it.

[anlauto]

...on another note....details in the engine compartment look fantastic

[Mrbill426]

@anlauto  thanks for that comment; coming from you who seems to have been doing this for a while that means a lot.    Right now though it's nothing more than pretty garage art.    I guess I really haven't posted many photos of this rig along the way; mainly just asking questions... I did on the old website during early rebuilding... here are a couple more... air cleaner still need a once-over.

...on another note....details in the engine compartment look fantastic

[Burdar]

There was recently a big thread on Moparts about this.  EVERYONE told the guy his trans needed to come out and be rebuilt.  He didn't want to listen.  I tried finding it but no luck.  Basically the consensus was that if water/coolant gets in the trans, it's junk.  The clutch discs will fail...soon.

[Mrbill426]

I have read that the adhesive used on the clutch discs is water soluble.  I am no automotive parts engineer but even though water does not belong in there, knowing the fact that it CAN and DOES happen, and a fluid flush would remove it, I would think there would be an incentive to use something more durable than Elmer's Glue.

There was recently a big thread on Moparts about this.  EVERYONE told the guy his trans needed to come out and be rebuilt.  He didn't want to listen.  I tried finding it but no luck.  Basically the consensus was that if water/coolant gets in the trans, it's junk.  The clutch discs will fail...soon.

[chargerdon]

Hmmmmmmm     i rebuilt my A518 automatic before installing it, including new clutch discs.   Many of the old clutch discs were still in great condition, and im pretty sure i saved some.     I COULD soak a couple of them in water with antifreeze for a couple of days, and then clean them off and see how the surfaces look for you.

Would this help ? 

[Mrbill426]

If you are willing and have the time it just might.  Be a good experiment either way.
Thanks

Hmmmmmmm     i rebuilt my A518 automatic before installing it, including new clutch discs.   Many of the old clutch discs were still in great condition, and im pretty sure i saved some.     I COULD soak a couple of them in water with antifreeze for a couple of days, and then clean them off and see how the surfaces look for you.

Would this help ?

[Rich G.]

I would disconnect the return line to the cooler, overfill the trans and start the car. Don't run the engine when the flow stops. Fill it back up and do it again. When it flows out nice and clean, hook the line up and top it off.

[Mrbill426]

@Rich G. on the transmission is the front fitting the outlet to the cooler, meaning fluid will be coming out of the transmission at that point?

I would disconnect the return line to the cooler, overfill the trans and start the car. Don't run the engine when the flow stops. Fill it back up and do it again. When it flows out nice and clean, hook the line up and top it off.

[Rich G.]

I don't remember which one it is so I'd disconnect both at the cooler and put some hoses on the lines and put them in a bucket. Have someone start it up for a few seconds and you'll see which one is flowing out.

[Mrbill426]

Yes, good point 

I don't remember which one it is so I'd disconnect both at the cooler and put some hoses on the lines and put them in a bucket. Have someone start it up for a few seconds and you'll see which one is flowing out.

[Dmod1974]

Make sure you do this in Neutral as well since the torque converter doesn't receive pump oil in Park in Torqueflites, and consequently little to no flow will be seen coming out of the cooler line either.  The torque converter holds a couple of quarts so you'll definitely want to make sure it is flushed.  Also, cycle through the other gear selections to circulate fresh oil through the clutch pistons, servos, accumulators, and valve body circuits as much as you can when stationary.

Once it's pretty clean, you still need to drive it around and put some miles on it and then drop the fluid at least one more time.  You want everything moving so the lube oil can push all of the old crap out and splash oiling to rinse everything in the case and gear train out.  Also, certain valve body circuits will never see oil flow without speed and gear changes since the shift valves and governor circuits won't do anything stationary.

[Mrbill426]

Hey folks thanks so much for all the helpful comments and insight; really appreciate it.  I have decided to drop the transmission back out and have the re-builder go through it again.  Delays our project (again) but gives us piece of mind that we will be less likely to be stranded far from home in the future due to a sudden failure.  We are getting up in years and just don't want that kind of hassle out on the road.  New exhaust system taken back out, and now waiting for an ordered transmission jack that was of course not is stock anywhere local.

Thanks again!