727 Trans cooler ?

[65 3 times]

I have an issue with trans fluid. It seems to be bleeding back to trans from cooler when sitting for a day. The setup is a 440 - 727 combo, race only, cooler is Derael 15 row super cooler with fan mounted located where the fuel tank was. This is plumbed with AN-6 line and fittings. Trans has 2 Qt xtra pan. I filled with engine in neutral, car elevated, to a level of add 1 pt.. The Trans works fine and cools well. I can make 6-8 passes and trailer home 1.5 hrs. with no leaks. I park in garage and in about 24 hour have lost fluid. Seems to be coming from area of dipstick like it is leaking at o-ring which is above the add 1 pint line. Do I need some kind of check valve in lines? (The cooler is above trans level but no higher than radiator cooler)

 

[Budnicks]

Sounds like a check valve is in order, self diagnosed...LOL

I never had that issue, sounds logical
but my cooler/s was/are usually more at the rear of the car
or by the radiator
no real room by the trans with headers & 3" exhaust
& come to think of it, my fitting were on the top too...
not as much back draining that way, I'd guess...

 

[dvw]

Fix the dipstick tube leak. 727 fluid level at engine off is above the level of that O-ring.
Doug

 

[khryslerkid]

My tq drains back on my truck and fluid will come out the top of the dip stick tube. I've learned to start it in natural if it sits for a period of time.

 

[66Satellite47]

My 2 cents, I agree with dvw. With engine off I'm sure level is sure above the O ring level. With a hot check & properly filled after warm up, the level is not much below that. Good luck.

 

[65 3 times]

I will change o ring this week. I'll let you know. Thanks DVW & 66Sat Dave

 

[Mike Gaines]

My 2 cents, I agree with dvw. With engine off I'm sure level is sure above the O ring level. With a hot check & properly filled after warm up, the level is not much below that. Good luck.

Lets have instructions on the proper way to check 727 Torqueflite trans fluid level...
Please post on this thread to see if everyone says the same procedure (or not )...

 

[66Satellite47]

To the best of my knowledge, warm the engine/trans up, run through the gears, then check level running in neutral. Should be in "normal" range.

 

[SUPERSTOCKRACER]

These transmissions arent made to have fluid above o ring in dip stick. Race cars take more fluid with deep pans, and you will always get some fluid out of there unless you pull dipstick,DRAIN FLUID DOWN PAST DIPSTICK 1st and put a bead of hi temp RTV silicone around the o ring and stick dip stick back in.
Wait over night and then add your fluid back in.
NO MORE LEAKS.

 

[65 3 times]

OK ... Drained pan, removed tube, cleaned all surfaces, new o ring and red silicon, tightened down and let cure, refilled and checked NO leaks.
Thanks to dvw, 66 Sat, SSR

 

[flyingfarley]

Could be the torque converter draining back into the pan when the car sits. My 65 Coronet has the trans cooler below the level of the cooling lines on the trans and still gains an inch or two in the dipstick when it sets for a week or so. Don't know how to stop that....must be a check ball in the trans somewhere...