Need Help - Transmission Oil migration?
 

On both my 1956 Ford T-bird and 1956 Mercury Montclair when sitting in storage, transmission oil is migrating from the Torque Converter back into the transmission pan. Anyone have any ideas why this is happening? Shouldn’t there be a check valve or stop to prevent this from occurring.

Re: Need Help - Transmission Oil migration?
 

If the front seal allows air to leak in, oil will leak back and out. The solution it to turn over the engine enough to keep the seal wet. During a long cold winter, you may wish to put a pan under it to catch what comes out.

Re: Need Help - Transmission Oil migration?
 

Happens with the C-4 in my car

Re: Need Help - Transmission Oil migration?
 

Same thing happens on my '51 MerOmatic.
Keeping any seal "wet" is not a solution.
The only thing that stops the leak (other than major overhaul) on the floor is to watch the oil level as it rises on the stick.
When the level is 1/2-3/4" above full, start the engine until the oil is pumped back into the converter. (good for several weeks)
The point of leakage (to the floor) is at the shift shaft where it comes out the side of the transmission.
If a suitable seal at the shaft could be installed it would stop the floor leakage but not any converter to pan leakage.

Re: Need Help - Transmission Oil migration?
 

The military always required a 14-day maintenance operational check or MOC along with PMCS or preventative maintenance checks and services. I pretty much recommend folks do that once every two weeks and it will keep thing working properly. I don't know too many motor vehicles that like to set around for too long.

Re: Need Help - Transmission Oil migration?
 

What you have is a bad front pump seal allowing the convertor to drain into the main case after engine shutdown.

The pan is designed to hold only so much at rest and the additional fluid volume and weight causes seal leaks and expulsion out the vent tube.

You need to have either have the TRANS pulled and re-sealed or look for a product that reconditions seals ONLY. No type of cleaner.

If you decide to re-seal, have the convertor re-sealed also as it will save you time and money.

The problem is age of seals and little use of the cars.

Both the BIRD and MERC have the mid-size case MERC-O-MATIC.