Mechanics

TRANSMISSION FLUID LEAKING FROM VENT HOL

2002 Ford Explorer

Transmission problem
2002 Ford Explorer 6 cyl Four Wheel Drive Automatic 124000 miles

Since July of 2009, my Explorer has been leaking transmission fluid from the vent hole while/after driving. I usually drive 40 to 74 miles each day, mountainous driving. It seems like the tranny needs to get hot before it leaks. It does not appear to leak once the tranny has cooled down completely nor does it leak while just sitting parked for several days at a time.

My local Ford garage finally localized the leak to the vent hole after initially thinking it was the transfer case gasket and transmission pan gasket leaking. They so far have been unable to determine why the fluid is coming from the vent hole since they have not yet opened up the tranny. They think that maybe the tranny fluid is possibly overheating and causing the fluid to expand to the point of leaking. They are currently attempting to connect some kind of gauge to the tranny to check pressures while/after driving but they are having difficulty getting the gauge connected due to the tight working space.

I am aware from your site that an internal leak could cause fluid to drain back into the tranny overnight, causing it to overfill and leak from the vent hole while parked overnight, however, my issue occurs while/right after after driving.

My tranny does slip a little every once in a while and sometimes will shudder a little after cresting the top of a hill when in overdrive. It also has occasional harsh engagement when in trying to put it in reverse. The garage has not seen any clutch material or metal chunks in the fluid the last few times they looked at it. Also, once after driving, the tranny would not go into any gear until it cooled down.

Could the solenoid pack cause all of these issues or could there be something more major at work? Could there still be some kind of internal leak that might cause these symptoms during driving as opposed to being parked overnight? Is a replacement tranny in my future?

I have been dealing with this for about 5 months and really need to get this resolved, hopefully before the snow flies. Thanks for your help!
Avatar
Midihead
November 20, 2009.



H midihead,

Thank you for the donation.

When trans fluids are overfilled, they would leak from the vent holes when driving. Did this problem occur not long after trans fluid replacement or topping up?

Overfilling would also cause the fluid to churn and foam and this would cause air pockets in the fluid system resulting in fluid overheating and shifting issues.

Symptoms indicates the fluid is overheating and apart from above, check the fluid cooler and its hoses for restriction which would not allow sufficient cooling.

The solenoid packs would not casue the problem unless they are causing the trans to slip and when this occurs, overheating of the fluid would occur over strenous driving as in your case.

KHLow2008
Nov 20, 2009.
Thanks for the reply. I had a transmission fluid flush done in February of 2009. Did not notice leak and slipping until late July. The garage assures me that, at the last fluid level check, the levels were where they should be.

Would the pressure tests they are going to do help to reveal restriction in the hoses or cooler? I'm not sure what is involved in checking the cooler and hoses for restrictions otherwise.

Tiny
Midihead
Nov 20, 2009.
No, the pressure test would not reveal any restriction in the cooling circuit. They would only be testing the fluid pressure for each speed that the trans is in to check if they are within specifications.

To check for restrictions, you would have to visually inspect the hoses ( kinks ), pipes ( distorted or bent acutely ) and disconnect the cooler to check/test.

Transmission flush is a no no for most trans. A fluid replacement and/or filter change is all that is required. Is the garage you send the vehicle to a certified Ford dealer? Hope they have used the correct fluid specifications.

Have you tried replacing the fluid again?

KHLow2008
Nov 20, 2009.
If the garage has not yet checked the cooler, hoses, and lines, I will make sure they do that next.

The reason I had the flush done is because my garage thought that whoever had the vehicle before me had another garage put the wrong type of fluid in the tranny. They recommended the flush to clear out the old fluid. To my knowledge, I think my vehicle takes Mercon V fluid which is what my garage says they put in.

Just prior to getting the flush done, the vehicle had been dropping out of gear and kicking back in harshly very regularly. After the flush, it stopped doing that and only recently started slipping a bit besides the leaking issue which started in July. My garage did use TransX right after the flush in February to help recondition the seals, etc.

They have added fluid over the last few months as needed due to the leaking and from when they replaced my transfer case gasket and tranny pan gasket but I have not had all of the fluid replaced again since the February flush.

Yes, my garage is a certified Ford dealer.

Tiny
Midihead
Nov 20, 2009.
If they have been topping up the fluid thinking it is a leakage, I would get suggest rechecking the level to ensure that it is correct.

I don't recommend any trans conditioners or additives as they might not be compatible with trans fluids operations.

Since problem occurred a few months after replacement of the fluids, we should not rule out the possibility of bad fluids and if they have not been replaced since, maybe you can give it a try and check the filter as well.

Before doing above, check the cooler fins for clogging, this would cause inefficient cooling of the fluids. If problem does not occur under normal driving conditions, the most likely fault would be inefficient cooling.

KHLow2008
Nov 20, 2009.
Service Manager at my dealership installed the gauge and drove the vehicle locally but could not reproduce the shuddering so far. He said the gauge showed nothing unusual. He said that he will try driving it along one of the more strenuous routes I normally take to try to get it to act up.

I asked if they had checked the cooler, hoses, and lines. He said that they hadn't yet. He stated that the gauge attached to my tranny will show temperatures. He said that if the gauge temperature doesn't show signs of overheating, he doesn't see a reason to check the cooler, etc.

Keep in mind that the Service Manager is currently not charging me labor on this continued investigation into my overheating/leaking issue since they previously misdiagnosed it back in August of 2009 by thinking it was the transfer case gasket and tranny pan gasket as the source of the leaks and charged me $700+ for those repairs. He is personally doing the current diagnosis, however, the process is slow since he's the Service Manager and can't work on my vehicle constantly. I'm trying to stay with my local dealer since I feel they need to make it right for not diagnosing it correctly the first time.

Tiny
Midihead
Nov 23, 2009.
Some weird problems do require extensive testing and diagnostics and since the dealership is taking responsibility and continuing to perform diagnostics, you would have to bear with them for the time being.

It is true that if the temperature does not increase, the cooler should not be the cause so we will have to wait for them to confirm it.

Sit tight. : )

KHLow2008
Nov 24, 2009.
Service Manager called and said they drove it over the last few days with the gauge attached in one of the same strenuous areas I drive in. The temperature reading did not show anything out of the ordinary, nor were there any shift problems showing up.

Service Manager said that his recommendation is, if it were his vehicle, to just drive it as it is. He said that he would hate for us to have to put a bunch of money into the transmission if that wasn't really the problem. This is not a very reassuring recommendation.

It appears obvious that they have no idea what is causing the problems based on the tests they've done. The Service Manager gave no indication what should be next steps if we decided to keep pursuing a solution to the problems.

Not sure what to do now. There is obviously a problem and I fear one day this thing is going to let us sit before long.

Your thoughts?

Tiny
Midihead
Nov 27, 2009.
When the test drive was performed, did he encounter the fluid over flowing as well?

When was the last time you encountered the problem?

KHLow2008
Nov 28, 2009.
I don't believe the Service Manager specifically checked for further leaking. He was mainly focusing on the gauge readings. He did not specifically say he checked again for leaking.

The last time it leaked for me (and would not go into gear until the tranny cooled down) was on November 7th which was the last time I drove it before taking it back to the dealer on November 9th. They have had it for 3 weeks now. The day I last drove it and had the " no gear" problem, it was a warmer day and all 4 family members were in the vehicle.

As long as the vehicle is driven consistently (several days or more in a row), it will leak. If it sits for while, short trips aren't enough to really make it noticeably leak until it is driven longer distances. The leak is slow enough that the dealer had trouble narrowing it down to the vent hole until they did the dye test recently.

I am supposed to get the Explorer back this Monday, November 30th. Seeing that nothing was done to correct the overflowing, occasional shuddering and occasional harsh engagement when putting it in reverse, I am pretty confident it will continue to do these things.

Tiny
Midihead
Nov 28, 2009.
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