Transmission Fluid: How much over is overfill?

S

sarity945

Joined
Dec 12, 2023
Messages
111
Vehicle: 2003 Windstar. Transmission fluid capacity : 13.6 quarts/dry

Yesterday i drained and refilled the transmission fluid and installed a new filter. I have couple of questions.

1- The last time a transmission flush was done on my Van was in 2014. Between 2014 and 2023 the Van had been driven only 17000 miles. Even though it wasn't being driven much yet all routine and required maintenace work were being done in the interim. I am curious, did i do the right thing by changing the transmision fluid/filter or was it unnecessary? The reason i ask is the fluid did not appear to have changed color much and seemed to be in good conidtion (at least visually).

The above question is for my own continued education ;-) but the question below is the concern and the reason for this post.

2- I may have overfilled the T.Fluid by half a quart or perhaps around a quart. Is this going to be a problem? The transmission pan does not have a drian plug so if i wish to remove any excess i will have to remove the pan again, which i don't want to mess with. Will there be any serious probelms? If yes, what are they?

Thoughts, comments, advice? Thanks
 
Last edited:
sarity945 said:
Are there any known issues if we are over by a quart? What are they?
Click to expand...
I'm not sure how can you not know how much its overfilled when it has a dipstick?

If its overfilled too much it can foam the fluid which has a bunch of nasty side effects.

The first thing to do is determine the transmission fluid level.

warm up vehicle/transmission
check dipstick running.
 
Opelman said:
If it is indeed over that much, a vacuum extractor is your friend. .5qt you probably can get away with.
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A 1/2 quart over, you should be okay. I would still check the transmission stick, when the transmission is good and hot, for any " foaming" ( air bubbles in the fluid ). Down the line, that can lead to poor shifting and leaks from fluid being over-pressurized. 1 qt overfill is too much IMO. Get an extractor pump, or you can disconnect a cooling line, and let the transmissionmission pump some fluid out. It's messy, but effective. When I do automatic transmission services, I leave the stick a little low, cycle through the gears, then go for a ride to heat up the transmission, then back in the garage, wait for the radiator fans to turn on, then off, then check the stick with the vehicle idling..... Sometimes it's dead on full, or I may have to add a little bit.
 
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50yr Street Mech said:
A 1/2 quart over, you should be okay. I would still check the transmission stick, when the transmission is good and hot, for any " foaming" ( air bubbles in the fluid ). Down the line, that can lead to poor shifting and leaks from fluid being over-pressurized. 1 qt overfill is too much IMO. Get an extractor pump, or you can disconnect a cooling line, and let the transmissionmission pump some fluid out. It's messy, but effective. When I do automatic transmission services, I leave the stick a little low, cycle through the gears, then go for a ride to heat up the transmission, then back in the garage, wait for the radiator fans to turn on, then off, then check the stick with the vehicle idling..... Sometimes it's dead on full, or I may have to add a little bit.
Click to expand...
This is my first time hearing about a vaccum extractor. Would you by chance direct me to some resources that show how to do it? Paricularly in realtion to transmissionmission fluid? Does the extractor extract from where the dipstick is located?
 
I've heard too much transmission fluid causes all the exterior seals to blow out from being over pressurized starting with the pan gasket.

Wives tale?
 
grasscutter said:
I've heard too much transmission fluid causes all the exterior seals to blow out from being over pressurized starting with the pan gasket.

Wives tale?
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Old wives' tale. There is a breather on transmissions to compensate for the air and fluid expanding and contracting as it heats and cools. And if you have a dipstick, it should vent before you'd blow a seal anyway.
Also the pan gasket is submerged and in the good old days were cork and the seals were lesser resistant rubber than today. So they often leaked anyway.
 
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CleanSump said:
Old wives' tale. There is a breather on transmissions to compensate for the air and fluid expanding and contracting as it heats and cools. And if you have a dipstick, it should vent before you'd blow a seal anyway.
Also the pan gasket is submerged and in the good old days were cork and the seals were lesser resistant rubber than today. So they often leaked anyway.
Click to expand...
I also hear about sliipping gears and shifting problems. Those ole wives tales as well?
 
sarity945 said:
If comprehension isn't your strong suit i suggest some lessons with your moderators. Now run along.
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Enough with the combativeness. Rand is a long, long timer on this site with a bajizzian non-trolling posts. I'm sure he was not intending to step on your feelers. Play nice, please.
 
sarity945 said:
This is my first time hearing about a vaccum extractor. Would you by chance direct me to some resources that show how to do it? Paricularly in realtion to transmission fluid? Does the extractor extract from where the dipstick is located?
Click to expand...
I don't own a " vacuum extractor", so I'm not familiar with it. There are " oil extractors" I've read about on BITOG. Not sure if they are compatible with ATF. I'd assume a vacuum extractor would utilize the transmission's dipstick port, same as an oil extractor normally uses the engine's dipstick port, if the engine is equipped with a dipstick. Sorry, maybe someone else can direct you better -( .. Good luck. Would hate to see you dropping the pan again if you decide to remove fluid. Messy job.
 
Limited knowledge here, but I believe there two types of extractors: electric, hook up to battery, run narrow tube down dip stick tube, and go; second type-easier and cheaper-hand pump (pump out, or pull up and create suction). Same process, run thin tube down dip stick tube and suck out small amounts (pumping out into a container). Try to measure fluid on the dip stick after removing a 1/2 quart and see what you get.
 
Sprintcar26 said:
Limited knowledge here, but I believe there two types of extractors: electric, hook up to battery, run narrow tube down dip stick tube, and go; second type-easier and cheaper-hand pump (pump out, or pull up and create suction). Same process, run thin tube down dip stick tube and suck out small amounts (pumping out into a container). Try to measure fluid on the dip stick after removing a 1/2 quart and see what you get.
Click to expand...
Thank you for this very practical solution on what to do.
 
CleanSump said:
Old wives' tale. There is a breather on transmissions to compensate for the air and fluid expanding and contracting as it heats and cools. And if you have a dipstick, it should vent before you'd blow a seal anyway.
Also the pan gasket is submerged and in the good old days were cork and the seals were lesser resistant rubber than today. So they often leaked anyway.
Click to expand...
So a 1/2 quart over won't hurt anything?

I'd like to run a little over since I got a leaky axle seal.
 
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