Oil leaks from gearbox breather hose - Explorer 2006 4.0 | Ford Explorer Forums - Serious Explorations

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Oil leaks from gearbox breather hose - Explorer 2006 4.0

Ahmed Ibrahim

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March 25, 2019
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Hello Everyone,

i was having a transmission oil leak from the radiator. I changed the radiator with a secondhand one and it looks clean and i'm not facing any heat issue with the engine, but I'm getting a smoke when I'm trying to accelerate and remove my leg from the accelerator.

After checking i found that the gearbox breather leaks the oil and get the smoke once it touches the hot engine parts. the mechanic said the oil level is ok and it might be an overheating issue.

any ideas how to diagnose the issue, and the best solution?


I checked the Transmission fluid temp using "Torque pro" and it was about 80c to 91c after driving more than 30 minutes with outside temp 26c.
so i think there is no overheat in the gearbox. but still getting oil leak from the breather hose when leaving the accelerator after 4000 RPM.


one more quotion: the gearbox breather hose, where it should be connected in the other end? becasue in my car it's not connected anywhere, it's just laying down

Ahmed Ibrahim

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I hate to say it but I dont think anyone has had a similar problem to yours. Is the breather line connected to the transmission case? If you could supply some pictures of where the oil hitting the hot engine and smoking and of the breather tube it may help.

Yes, please post some photos.

Now there is no smoke because the mechanic changed the breather hose direction to spill the fluid on the ground. but of course this is not a solution.

when I leave the accelerator the oil start to come out from the breather hose, also i noticed there is a water coming from the exhaust when i leave the accelerator
the transmission fluid looks very clean after driving more than 1500 KM






The mechanic said that this issue might be from
1- Overheating
2- solenoid block
2- Transmission pump

opening the gear and trying to fix the solenoid block and the pump will cost same as if i get used gear and install it. but still both solutions are costly, beside it doesn't look that the mechanic is confidant that this is the cause of the problem.

if the problem from the solenoid, then it should not cost too much, but the pump will be so costly with the labor work.

is it a coincidence that i have this leak and the water from the exhaust?

also i tried to monitor the temp using the OBD2 Torque pro, but some sensor didn't read.
however i added the "Transmission Temperature" and it was not reading, but it gives one read 159.9c "320f". it didn't go up or down while driving but it seems very high.
the "Transmission Fluid Temperature" was 82.7c

what is the deference between the "Transmission Temperature" and the "Transmission Fluid Temperature"

The condensation from the exhaust completly normal. When you burn fuel its creates some water vaper that will condense on the cooler parts of the exhaust creating liquid water.

Take a look at this thread I believe what is circled in the picture is the transmission vent line. yours looks to be disconnected from where its suppose to go or broken in half.