Cold snap, then fluid on the ground

[Cherryriver]

We recently had a pretty fair cold snap, when the overnight low hit -9F (-23C) and I used my '03 5.4 AWD for my usual workday driving. Later on I noticed a small dark circle underneath the vehicle.
Now a few days later, the car's been sitting not needed and there's a good-sized puddle on the pavement and taking a quick look underneath things are pretty wet at the rear of the engine/front of the trans area.
It will be going to the shop for a better look when I can get it in, but just to give me something to fret over, care to guess? Again, the fluid is dark-ish and seems to mostly be coming from the front of the bellhousing.
Something's telling me this is a fatal leak for an older vehicle with 190,000 miles (305Kkm), especially if it's the front of the trans.

 

[whtbronco]

Dark could be motor oil or old transmission fluid. A paper towel with some of the fluid soaked into it will give you a better idea of the color. The color will help determine an engine or trans leak.

 

[BigOleFordFan]

"Houston, we have a problem"

Better get it up on a rack soon to determine where the leak is coming from...at that mileage it could be several things, all of which are probably fairly expensive to repair....

Then the question will be "is it worth fixing, or more feasible to ditch it & get something else/newer" ?

 

[BigRed2004]

I agree with @whtbronco of using a white paper towel to 1st determine what fluid it is. My first thought was a rear main seal on the engine. Have you checked your oil and transmission fluid levels? This could also help you figure out what the fluid is.

 

[Cherryriver]

Well, a little time has passed, and things were busy such that I wasn't able to get the Expedition to the shop for them to look at it.
But in the meantime, I still had to drive it a bit, for one thing. For another, the temps went up, pretty well up. We're seeing 50+*F today.
And the leak pretty much stopped. After a 15-mile drive to a worksite this morning with temperatures just below freezing, it sat for 2 1/2 hours and then there wasn't a spot on the ground underneath. In fact, I am not seeing anything.
So, given there are some other life happenings going on I'm just in watch-it mode for now.
The engine oil is down a bit less than a pint after 2000 miles since the last change and the trans fluid is fine. Neither is showing any funny coloring, either and the trans seems to be shifting smoothly and quietly.
Holding pattern.

 

[BigRed2004]

Sounds like you may of had some contraction from the weather that may have caused some slight gapping in one of the seals. But this is only factoring the weather, can’t say without more information. But it is good to hear nothing has gotten worse. If it happens again I would suggest some photos to help us help you where we can.

 

[whtbronco]

Sounds like you may of had some contraction from the weather that may have caused some slight gapping in one of the seals. But this is only factoring the weather, can’t say without more information. But it is good to hear nothing has gotten worse. If it happens again I would suggest some photos to help us help you where we can.

I agree.

That said if it was simply due to the low temps it will occur again and it will get worse. Even if you chose not to resolve it soon I think identifying the cause is important.

 

[SafariGoneWrong]

The only fluid I have seen spill onto the ground due to temperature change is coolant. My RV, Bronco, Passat are all offenders. I’m also wondering if barometric change is a factor. Only thing I can think of is maybe a head gasket, but I’d think there would be secondary indications if that were the case. Last thought, take a look at the dipstick tube where it enters the transmission case. Those 4R75s aren’t like a C6…the fluid level is above the tube o-ring. Boy was I surprised at the amount that poured out when replacing my right bank upstream O2 sensor and exhaust manifold.

 

[Cherryriver]

A minor update a couple of weeks later: still nothing on the ground since that first event.
On the other hand, we're supposed to go below zero F tonight; the forecast is three below. I'll be looking.

 

[BigRed2004]

Did the weather seem to have an impact this time?