1949 Dyna flow question

[Brooklyn Beer]

This is the second time this has happened in 4 years.  The first time after a 1600 mile trailering. The second time sitting when temps dropped to 3 degree's.  A huge puddle of trans fluid.  It just seemed to drain 2 quarts on the floor.  (it took 2 quarts to fill back) Each time I refilled it and it didn't drain out. Each time I started the car after the episode and added fluid to the full mark very slowly, letting it warm up.  Each time after shutting the car off and checking it when cool it was now over full.  Start the car it goes back to normal. Drives fine.  After a couple drives the fluid level remains normal. Is there a check valve of sorts somewhere that is getting hung open?  Running Dex/Merc

Edited April 4, 2023 by Brooklyn Beer (see edit history)

[JohnD1956]

Those are inconsistent leak symptoms.  It sounds like the trans fluid was checked while the trans was cold?  It should be checked at operating temp. But in either case it is unlikely the trans dropped 2 quarts at one sitting unless you have a deep drip pan under it because that is probably enough to coat the floor of a large garage.  Just where it is leaking from would be a wild guess on anyones part.  We would need more evidence such as oil traces on the frame and underbody pans? But there is the usual culprits such as the torque ball seal, the accumulator seals, and the front pump seal.  As for being low and then overfilled it would appear any internal check valve that would keep the torque converter full, while not in use, is working. Is this for the 49? There is a section of the 56 manual that goes into some trouble shooting of the dynaflow leak situation. Does the 49 manual have something similar?

[NailheadBob]

Follow John's suggestions, and I would also add transmission oil dye to your transmission and then use a ultraviolet light with special glasses to see where the dye is coming out.

 

Bob

[Brooklyn Beer]

Thanks for replies.  I will move it onto the lift this weekend and get it in the air after driving and see if it is leaking from the above mentioned places. It has been a week since I refilled with 2 quarts after seeing the puddle. Ran it up warm and added 2 quarts to normal.  Now cool and showing overfill after 4 days of sitting.  No new puddles.

[avgwarhawk]

Probably showing over full now that it is cool.  Possible the fluid is draining out of the transmission body into the pan.  Once started it circulates once again and shows at the full mark once warm.  Also, I suspect at 3 degrees a seal probably shrank allowing fluid to leak.  I have a plastic tank radiator that would leak where he plastic tank and aluminum fins would meet.  The seal between would shrink in the cold allowing antifreeze to leak.  Took me a few times to convince the dealer the radiator was bad(under warranty).  

 

My best guess with leaking while trailering...possibly the fluid was flowing reward while in transit on the trailer. The fluid then came out of the breather tube on transmission.     

Edited April 11, 2023 by avgwarhawk (see edit history)

[EmTee]

On 4/11/2023 at 1:53 PM, avgwarhawk said:

The seal between would shrink in the cold allowing antifreeze to leak. 

NASA identified the same issue with Challenger.