Trans Fluid Pushed out Through Fill Tube

Josh,

This transmission takes Dexron. The fluid level being high could cause this condition so get that figured out first. Assuming it is correct the next most probable fault would be a blocked vent. As the trans gets hot it has to vent and if it can't it will vent out the dipstick tube bringing fluid with it. This will occur worst after a long high speed drive. Can't remember where the vent is on a Powerflight but my guess would be at the top rear. I have one sitting in my shop so I'll check it tonight. The other thing that could cause this would be a large internal leak caused by a bad seal or worn bushings. Probably not the case since you say it shifts OK.

Tim

Hi Josh-I had a similar problem with a 55 Desoto Fireflite with water cooled tranny I restored. The transmission and engine were out and both rebuilt. I drove it about 200 miles on 20-30 mile max trips in Spring weather with no problems.
When I put the car on the turnpike at 70 for a trip of 150 miles to Philadelphia in warmer July weather I was following the car in my truck. After about 50 miles it began to trail oily smoke. When i checked the dipstick after a cooldown for a bit, it showed a good level of fluid but it was obvious fluid had leaked out from various spots including the dipstick tube.
Had the car sent back home on a rollback and went on to Phila.
The trans. rebuilder pulled the trans. and went over the things he'd done. put it back together and I gave it another try-same thing on a hot day-a trail of oily smoke and pressure leaks.
Long story short-the torque converter which is welded together had not been sent to a specialist for a complete disassembly. I think a valve in the torque converter was malfunctioning causing the torque to download most of its fluid to the main body which was not designed to hold 8-9 quarts of fluid.
A complete disassembly of the torque converter and rebuild solved the problem.
I'm sure I won't consider an auto. trans rebuilt until this job has been done in future.
I hope this isn't your problem. Checking the fluid level is important-according to the Desoto Shop Manual you should warm up the engine and trans. for 2 minutes at idle and check the level with engine running and in the neutral position. The level should be no higher than 1/2" above the low level on the dipstick. I've had no such problems with my own 55 and don't think the torque converter was disassembled when the trans was rebuilt. Count me among the lucky.
One more point-Almost every 50s auto trans. car I've owned has downloaded over the Winter leaving a 2 qt puddle on the floor-a 2 qt fill and driving in the Spring seems to solve the problem til next Winter. My 55 Desoto is no exception.
Filling procedure when the trans is empty is to initially fill with 4 quarts then start the engine and add more quarts til the dipstick comes up to the low level mark. A cautionary note states that overfilling will cause the oil to come out the dipstick. Total fill shouldn't be more than 8-9 quarts.
Martin Lum
55 Desoto Firedome and 55 Desoto Fireflite

I have a 53 and it does not have a water cooled trans. I have never seen this problem in my 50's era DeSoto. So maybe Josh could luck out and find that the coolant system to his trans is not working well. It is always better to make sure the easy and inexpensive work is done correctly first. Just my 2 cents worth but it is the way I like to tackle challenges.

A couple of thoughts. Do you have the correct dipstick and/or dipstick tube?? A '55 Firedome has an air cooled transmission. Are your screens clean on the TC housing? These are commonly clogged with crap. Could be getting hot.

I have a '55 Firedome and can see the transmission fluid level easily on the dipstick. This is good because it does leak down over winter as Martin said. And, he is correct, if everything else is right, it might be a worn out torque converter.

Have a nice day
Steve

hey guys, im sorry that i havent replied to your suggestions. for some reason i am not getting notifications of replies to my threads. anyhow, thank you all for your comments and suggestions, i will check all of these items. i do agree about trying the simplest items first so i think im going to start by draining all of the fluid out and starting over again. i was also wondering about a trans cooler. ill have to check the screens and the vents. i certainly hope it isnt the torque converter, but since it doesnt seem to happen at all in my daily jaunts around town, i dont think this is the case.
im also not sure about the dipstick being the proper one as i have nothing to compare it to, however, i did notice that id doesnt exactly lock into place in anyway and it is pretty loose ontop of the tube but as i said, i have no idea if this is normal as i have nothing to compare it to.
i blew a bushing out of the shock in the front as well this past weekend and i got a new set on the way so i will be working on that, the brakes, and this trans problem at the same time.
i also saw that i should be using dextron fluid. can you be more specific about the proper fluid. the last time i went to shop for this stuff, i saw a few different kinds of dextron.
thanks again everyone, i really appreciate your time, experience and suggestions.

Josh
BAMBAML19@AOL.COM

Josh,

You need Dexron III (3). I checked and the vent is at the top rear of the case. It may be hard to get to so the rear crossmember may have to come out. You can remove the vent with an open end wrench, 7/16 I believe. You should be able to blow through it. If you are having a hard time reading the fluid level after a high speed drive and it looks foamy that is not good. That would point to an overfilled transmission or worse, an internal leak probably cause by a worn bushing. I don't agree with the bad converter problem. The converter does not have any valves it it. There is a pressure regulator valve and other valves but they are in the case. Having said all that the internal leak could be where the converter meets the front pump. That bushing is known to wear and cause a host of problems like foaming and converter leak down after a long period of non use. And yes, it is very important to clean out the cooling screens. Good luck.

Tim Mabry

thanks tim, ill check the vent and the screens. the fluid isnt foamy though, so hopefully that is a good thing. i read the service manual and im going to check all the above items as well as draining and refilling the trans up from scratch again. i need to put some new shocks on her this week so hopefully by the end of the week, ill have this figured out. thanks again for the help everyone.

Josh

well, i replaced the shocks today and did a bit of peaking around at the trans problem. i couldnt find the vent that you were speaking of tim, i even reached my hands up and around the entire trans and didnt feel anything that stuck out as a vent. i also saw the screens on the bottom and both sides, but they looked like they were fastened on there with rivets and i couldnt see a way to remove them. im sure is something simple and i did have a brief look at the service manual but i didnt see anything in particular about them. is there anyone that can post up the page or an actual diagram of the vent on the trans as well as an idea of how those screens come out, i hope they arent just clipped in there, i didnt want to pry on them and damage them.

oh, and off topic, i had to remove the muffler to fix something else and i didnt realize how bad ass this car sounds sans muffler, i might even drive it like that !!!

thanks
Josh

The vent is at 12:00 where the cast iron case meets the aluminium extension (rear) housing. It's not real big, about twice the size of a valve stem cap. It similar to a vent you'll find on most rear axles. I'll try to take a picture when I can.

You don't have to remove the screens to clean them. A can of brake clean, wire brush and compressed air will do. Or you can go to a car wash with a small jack and blast them with water. Not the easiest way but it works. The main thing is they have to allow air to circulate. I've seen these screens completely caked shut from grease and grime.

Tim

yeah, a pic would be great tim, and yes, my screens were packed with grease and crap !!!

i know this sounds stupid, but i havent ever owned a hemi, or an older carbureted car before so this may seem silly. but i drove the car twice since i took the exhaust of just before the muffler and it stalled out once each time, but only when i stopped at a light and went to tap the throttle. the stalling wasnt the problem, its that she just wouldnt start back up, no matter what i did. both times i just had to let her sit for a few minutes, then try to start her up again and really pump the gas, she sputtered, rumbled, then caught, and stayed running with alot of coaxing. after she got running again, she stayed running and drove and idled fine. what gives? i ask this in reference to the exhaust because i have been driving her around for months and never had this happen til i removed the muffler. sorry for the stupid question, but i think its odd.

thanks
Josh

Josh, by removing most of the backpressure in your exhaust system, you are allowing more air to flow through your engine and the carb has not been reset for the leaner condition. Engines are way more sensitive to a lean condition than a rich condition. Or it could be your accelerator pump, just coincidentally.

Right paul, i had thought about the increased air flow situation. i happen to know that i do need to rebuild the carb eventually though as i am certain that the accelerator pump needs repair and it is leaking a tiny bit of gas. when i first purchased the car, i noticed that during pull aways and light throttle from stop, it would hesitate. i know this is symptomatic of the acc pump and im thinking that the problem has been exacerbated by the increased air flow of the exhaust.

i drove the car all day today as well and didnt have any stalling problems, i just make sure that i dont blip the throttle at a light for the fun of it.

i am procrastinating the rebuild of the carb, even though i know it isnt a difficult job, nor an expensive one, as there are kits out there for this exact carb, but im afraid that ill open a can of worms and find more things i need to work on and wont be able to enjoy the car. so my thinking, albeit flawed, is if she is running, and pretty well right now, im going to wait til winter to do the carb.

there are so many things that need to be addressed such as every rubber seal and piece of weather stripping on the car, but i have learned to take things in small projects at a time. as they always say, how do you eat and elephant....one bite at a time! although i much prefer the taste of a burger!

Thanks
Josh

Josh,
Here's a picture of the vent taken from the rear of the transmission looking down. It's at the end of the white pointer.

Tim

great, thanks alot tim, i really appreciate it !!!