1950s 1959 Cadillac transmission intermittent leak

[Cadillac Jack 82]

My 1959 Cadillac has recently been leaking transmission fluid.  I assume its due to the fact that the car sat for a while and wasn't used.  The issue I have is that when I ensure its topped off it'll leak fairly steadily but then stop.  I've read some past posts and I've seen posts saying its the filler tube gasket to the front seal by the flywheel.  Does anyone have any past experiences with this or suggestions?  The leak mainly comes from the front so I doubt its the rear seal.  It also seems to shift fine both with light and heavy acceleration.

[Jeff Rosansky CLC #28373]

It only leaks intermittently??
Wow!! Wish mine would do that 

I'd clean it, fill it, let it run and then climb under to see if you can see the leak's starting point.
Jeff R

[Cadillac Jack 82]

I know its very odd.  Leaked like crazy when I pulled it out.  Checked the level at home and it was normal.  Perhaps my dumba$$ overfilled it?

[TJ Hopland]

Is that a model that is tricky to get the level right?  Anyone with the same model describe how they are checking the level?

[Daryl Chesterman]

I drive a 59 Deville and the method I use is to start the car and with a foot on the brake, I shift into the first forward gear, wait a few seconds and shift into the second forward gear, wait a few seconds and shift into the next forward gear, wait a few seconds and shift into reverse, wait a few seconds and shift into park.  Get out of the car, leaving it running—lift the hood and remove the transmission dipstick and wipe it clean.  Reinsert the dipstick until it bottoms out on the dipstick tube and withdraw the dipstick and keeping the bottom end of the dipstick down, read the level of the oil.  When  cold it will read about halfway between the two marks, and when hot it should read at the full.  The Service Manual says that when fluid is cold the level should be 1/4" below the full mark.  By running the transmission through the range of gears, the fluid coupling is filled and all of the valve passages are filled, thus ensuring an accurate reading on the dipstick.

Daryl Chesterman

[Cadillac Jack 82]

Welp still tracing this little gremlin.  She will nearly pour trans fluid then she'll be fine.  After a long cruise today came home to find a nice pond of trans fluid however the dipstick reads full with the engine off.  With it on she'll read 1/4 full.  Shifts fine and no other issues.  Am I using too much fluid or is the front seal failing?

[V63]

Generally... The factory recommends checking fluid on a level surface, components operating temperature, WITH the car in park and engine running, (idling).

Verify the stick is seating into the tube fully. Might also verify the stick is a factory one and not a "replacement"  because a replacement could introduce errors in calibration.

[Cadillac Jack 82]

I'll take a look at it over this weekend when I have her back out from her garage.