Transmission losing fluid

[isensee]

I have a 1964 Avanti with the Powershift automatic transmission. The transmission pan gasket was leaking badly so I replaced it. I put about 4 quarts of Dextron-III fluid in and figured I would add the rest based on the dipstick level. The fluid level shows above the full mark with the engine off and then doesn't reach the bottom of the dipstick when warm and in drive. When I started the engine, fluid came shooting out of the dipstick tube landing as much as four feet away. Could being low on fluid cause that? Should I just add more or will I end up with even more fluid shooting across the garage?

Looking at the parts manual, I see there is a breather valve. I am wondering if that is clogged causing pressure to build up. That might explain both the earlier gasket leak and fluid shooting out of the dipstick tube now. Is that likely? The parts manual doesn't clearly show what the breather valve looks like or where it is located. Can someone direct me to it? Is there a way to clean it without having to drop the transmission?

Any other ideas?

I haven't driven it since replacing the pan gasket, but it was shifting just fine before. Keeping fluid in it seems to be the only concern.

[Sisensee]

I found the breather valve. I blew some air into the dipstick tube and I can hear it come out through the breather valve. So I think I can eliminate that as the cause of the problem.

[isensee]

I guess I’ll try adding more fluid and hope it doesn’t blow all over.

Edited June 6, 2020 by isensee

[mfg]

I used to own a '64 Avanti that would occasionally discharge trans fluid up the filler pipe upon start up.... IF I let the car set for two-three weeks between 'outings'.

Although I wasn't sure , I thought at the time the problem was related torque converter 'drain back'.    (overfilling the transmission main case.)

[isensee]

That makes sense. Could be at least part of my problem. Thanks.