Thats a weird one..
Are you sure that your pan is flat. You will bever get trans to stop leaking if the bolt holes are even slightly deformed. My guess is that fluid is up in the trans during running condition and leaks down after it is shut off and cools. This fills the pan up and it leaks out the gasket. Have you noticed a major change in fluid level on the dipstick. I would guess a 3 ft dia puddle would be noticeable on the dipstick. If it reads full still (while warm and running) I would guess it was overfilled. Did you try cleaning the outside of the trans with carb cleaner and then look for wet spots after it sits overnight?

 

It's up on stands now. I plan to get under there and do a thorough cleaning, and then run the car in gear with the parking brake set for 20 minutes or so. Then I'll shut her down, put on my camo, hide in the tall grass, and wait for the little red bastards to show themselves. Then I'll jump em.

I wouldn't be surprised if it's the pan gasket. I hammered the holes flat, but had a hell of a time getting the tranny installed. I probably disturbed the pan seal. We'll know soon enough.

I was just hoping to hear someone describe the overflow characteristics of these trannies.

 

I have an FMX on my 71 Mach 1 that is doing the same thing. Doesn't leak while running but when you shut it off, there's a leak. I looked in a diagnosis manual under leaks and one of the possibilities was a bad bushing in the front pump/converter allowing fluid to leak back into the transmission after the engine was turned off. This would result in the excess fluid draining out the vent tube.

 

Change your O-Ring on the transmission dipstick tube!! /forums/images/icons/wink.gif

There is no overflow feature in a C4. /forums/images/icons/smile.gif

Erik

 

Your problem intrigues me, because I had a similar problem on my '65. When I'd garage it over the winter (several months), it would suddenly leak a bunch of fluid. I would come out one day during the winter, and there was a big pool of AT fluid running out from under the car. It, too, came from around the pan. During regular driving, stop and go, it wouldn't leak. Unfortunately, I never did find the solution to that problem.

BTW, it continued to do this even after I had the C4 trans rebuilt, so they missed the problem, too! (???) /forums/images/icons/frown.gif

 

I'm beginning to think that leaking is a feature of these trannies. I thought I had mine licked last week when I replaced the cooling lines. Two days without that red pond underneath. Third day there is was again. Mine doesn't seem to be coming from the O-ring. Tomorrow I'll be under there again.../forums/images/icons/crazy.gif

 

I'd like to be there to witness you run the car in gear for 20 minutes with the E-brake on. *LMAO*

 

Back in 1965 my brother-in-law bought a new burgandy/black '65 coupe. Whenever he braked hard, ATF spilled out of the dipstick tube onto the exhaust manifold and caught fire. Ford never fixed this problem although they tried several times. My brother-in-law wanted them to install a replacement tranny but they never did. In disgust for FoMoCo, he sold the car in late '65 and bought another brand. To this day he's not overly fond of FoMoCo products. Sometime about a year ago, I read a web comment on the problem and the solution. It only took 35 years for someone to figure out what was wrong. Hope you don't have to wait that long to get an answer.

 

I had a C4 tranny rebuilt in a 67 vert that did the same thing AFTER the rebuild. It was the dipstick tube. Those fine folks at the tranny shop needed 4 attempts and two dipstick tubes to fix. I could never anticipate when it would dump its fluid, but it was always when I wasn't looking and after the car was parked.
Take a good look at the fit and make sure your gasket is good.

An interesting sidenote to all who get their C4 rebuilt by a so called reputable shop:
They swapped my 67 tranny for a different one without telling me. They told me they were rebuilding my original. I didn't realize until about 8 years later and the shop was gone.

 

I'm still putting my money on the O-ring. This is often overlooked. When the motor/trans is running, the fluid is constantly moving around in the trans/converter. When you shut the motor off, the fluid comes back down into the pan causing to fluid to run out of any "non-sealed" areas.

Erik

 

There most certainly is an overflow feature on our C4 trannies. Take a look sometime, and you'll see an overflow tube just above the neutral safety switch.

I'll replace the dipstick o-ring and rtv.

 

Umm, that's a vent. /forums/images/icons/wink.gif

If you have fluid coming out of there, you filled it too much. Fluid should NOT come out of there. /forums/images/icons/smile.gif

Erik

p.s. The only overflow tube in your car should be the radiator tube.

p.s.s. I don't think it would be environmentaly friendly to have a transmission fluid overflow tube come out and just pour away into the streets and waterway systems. /forums/images/icons/tongue.gif

 

I think that's why they call it an overflow tube. If I have fluid coming out of there, I assume it's because I put too much in...which is a real possibility, since I just installed it.

And the overflow on your radiator isn't anymore environmentally friendly than the one on your tranny.

 

Ok, it's real purpose is to vent the transmission.

And the radiator should always have a catch container.

Erik

p.s. About 8-9 quarts with the torque converter empty and about 5-6 quarts with the torque converter full.

 

Just re-reading the thread and my apologies if implied an attitude. I hope you find the solution to the leak ASAP. /forums/images/icons/smile.gif

Have a good weekend.

Erik

 

For the curious out there, how is the dipstick o-ring changed? If the dipstick just pops out then where does the o-ring come into play?

 

The secret is Cruex in the spray can. Yes, the jock itch stuff. Old motorcycle mechanic trick. Buy a can.
Clean the tranny thoroughly. I like to finish it off with some brake cleaner spray. Let it dry. Spray hell out of the whole thing with Cruex. Use the whole can if necessary, ALL over the tranny. Do whatever you think will make it leak, including sitting overnight. Then grab your droplight and investigate. The Cruex will show a nice dark red snail trail where ever the leak is coming from. Once you've found the leak the Cruex is very easily washed off with water. Try it.
It works on engine oil leaks too. The trouble with tranny fluid is that is blows all over the tranny until God couldn't tell where it started from. The Cruex slows it down enough to track it, unless you drive in the rain or through a big puddle.
P.S., hide your extra can. I always keep at least one around. If Swmbo happens to spot it she'll always have to make some sort of embarrassing comment.