Water in transmission fluid?

[Yota94]

Hoping to calm my OCD here a little with some feedback from you all.

Long story short, is .018% water content in ATF enough to cause damage or be of any concern?

I have a 2022 4Runner with 15k miles on it. I went off-roading about 2 months ago and got mud all over the undercarriage. I spent an hour under the car with a garden hose and a pair of diving goggles to throughly clean off the mud since I didn’t want it to trap moisture against the frame and cause rust to form. It didn’t occur to me until a week ago that the transmission breather is a 2 way breather and after checking where it lives, I’m pretty sure I hit it directly with a garden hose on full blast.

I ordered the exact breather and some vinyl tubing to make a test setup to see how much water I could have introduced in the worst case scenario.

I measured the distance from where the garden hose nozzle would have been to the breather on my 4Runner and the rough angle at which the water would have hit it at. I figured worst case scenario I hit it directly with the garden hose for 30 seconds so I went out and sprayed my test setup in the same manner for 30 seconds and measured how much water it collected.

I measured 2ml of water collected. My transmission has a capacity of 10.7l according to what I found online. I calculate that to be about .019% water content.

Is that enough to cause damage or be of any concern? I’m contemplating sending a sample in for analysis or potentially doing a drain and fill/transmission fluid exchange. What are your thoughts?

 

[totegoat]

I'd drain it.

 

[oldcodger]

I do not think transmissions are tolerant of dirt and water. I also would say service the unit.

 

[SC Maintenance]

water in the trans will corrode thing that aren’t supposed to corrode. This is one of the failure modes of SMOD.

 

[Chris142]

Water will destroy a transmission. It removes the glue like material that holds the friction material to the plates and bands. You don't have a whole lot but a few drain and fills is in order sooner than later.

 

[Klutch9]

2ml? Probably evaporated after the first couple long drives.

 

[proveitwithdata]

im intrigued by this. So undercarriage washes are no bueno i guess?

 

[Marcozi]

How did you determine the percentage of water in the ATF?

 

[demarpaint]

Water inside an automatic transmission can wreck it.

 

[Yota94]

How did you determine the percentage of water in the ATF?

I measured how much water my little contraption captured when I sprayed the breather with the garden hose and then divided that by the capacity of the transmission system.

2ml? Probably evaporated after the first couple long drives.

That’s what I’m hoping. I put about 3k miles on the odometer since then and I’m hoping if any issues were to come of it that they happen within my warranty and the water would be undetectable.

I thought about submitting an oil analysis sample for peace of mine but I’m not even sure if the Karl Fischer water detection test can detect ppm of 200 or less (my rough calculations puts 2ml of water at about 190 ppm)

 

[tnt_motorsports]

I measured how much water my little contraption captured when I sprayed the breather with the garden hose and then divided that by the capacity of the transmission system.




That’s what I’m hoping. I put about 3k miles on the odometer since then and I’m hoping if any issues were to come of it that they happen within my warranty and the water would be undetectable.

I thought about submitting an oil analysis sample for peace of mine but I’m not even sure if the Karl Fischer water detection test can detect ppm of 200 or less (my rough calculations puts 2ml of water at about 190 ppm)

FWIW I would have to believe condensation might produce this much water in your ATF. I'm guessing after the 3K miles you have traveled has "burned off" this moisture. Have you pulled the dipstick to see if there is any signs of milkyness?

Just my $0.02

 

[zulf200]

2ml in a 10L capacity is called negligible, just parking your car overnight in fall in the southwest can cause more than that volume to settle in the trans, diff and engine.

 

[02SE]

Your experiment is not conclusive one way or the other as to whether there is water (and how much) in the ATF. Your transmission is 'sealed' meaning no dipstick. But it has a fill plug, a drain plug, and a full when at the proper operating temperature overflow plug. I might pull the overflow plug (clean around it first) to see if any fluid comes out, have a clean, clear container to catch any fluid in, so you can see if any water is present in the fluid.

If there were water in it in any significant amount, you would likely have noticed erratic behavior of the transmission in the last 3k miles.

 

[nascarnation]

Glycol (antifreeze) can be big trouble for friction plates, but water in small amounts should not be an issue and will evaporate off when operating temps are above boiling.

 

[Yota94]

Your experiment is not conclusive one way or the other as to whether there is water (and how much) in the ATF. Your transmission is 'sealed' meaning no dipstick. But it has a fill plug, a drain plug, and a full when at the proper operating temperature overflow plug. I might pull the overflow plug (clean around it first) to see if any fluid comes out, have a clean, clear container to catch any fluid in, so you can see if any water is present in the fluid.

If there were water in it in any significant amount, you would likely have noticed erratic behavior of the transmission in the last 3k miles.

Thanks for the feedback. I haven’t noticed any issues with the transmission over the last 4K miles now so I’m hoping that means this is a non-issue and I didn’t actually get any water in the transmission via the breather vent.

Once the weather warms up a little I’ll check the overflow plug just to see although I doubt I would be able to tell. From what I’ve read the amount of water I potentially could have introduced (if I did at all, I’m just thinking through worst case scenario) would only be about 200ppm and the transmission fluid would show signs of free water until around 600-800ppm.

 

[Jetronic]

How did you determine the percentage of water in the ATF?

2ml to 10700 ml of oil... not that hard

and if he gets the transmission warm it'll all be gone

 

[Kira]

I would have to believe condensation might produce this much water in your ATF

^^THIS^^. The percentage given is ~one fifty-fifth of one percent water.
The vehicle while being driven normally heats and expands the fluid. Contracting as it cools, it creates a partial vacuum and draws moist air in through the vent.
This tiny bit of water effects whatever it will.
It should be driven out of the fluid by heat but that is never going to be a 100% efficient process.
Moisture will be in ambient air throughout our lives so this dynamic will recur constantly.
This is one reason to refresh fluids. How often you refresh your fluids is to be determined.

Brake fluid absorbs moisture to protect system parts. It reaches saturation and needs to be refreshed.

 

[KrisZ]

Let’s not panic and spread doomsday scenarios around just yet IMO.

If there was any significant amount of water in the ATF it would have turned milky pink color, just like engine oil, minus the pink color. If the ATF is still nice and red, there is nothing to worry about.

Edit, found some pictures for reference