1998 Explorer 4.0 Auto blowing fluid from vent

[jhow1]

A friend was driving in the mountains with a carload of people when her friends behind her spotted fluid and smoke from under the car. They pulled off right away and had the car towed home.
The next day I cranked the car, idled it for ten minutes, shifted through all the gears, drove it around the yard, drove it slowly for a half mile down a dirt road (gears change fine). All the time I'm looking for leaks and finding none. Further inspection shows a clear leak pattern from the vent tube back. Everything ahead of the vent tube is bone dry and the fluid pan behind the tube is clean of the grime covering the rest of the underbody. My assumption is that the transmission overheated and boiled fluid from the vent. The fluid smells extremely burnt.
She had the tranny rebuild a little over a year ago and it has been running fine since however she did say it had seemed sluggish lately.
I know a healthy transmission doesn't overheat under normal conditions such as this. I plan on doing a fluid filter change and flow testing the cooler. Anyone else ever have an experience such as this?

 

[david4451]

By any chance did she leave the hand brake on? I did on my ST just after receiving it new (8000 miles on it). Threw the oil out of vent and started a small fire which was put out immediately, but the damage was done and had a rebuild done.
That was 15 years ago and my 5r55e is still fine, however it's an embarrassing event I dislike recalling!
The ST did drive around in limp mode with OD light flashing.

 

[jhow1]

I will certainly ask her about that. They drove about sixty miles before the thing gave up.
The dashboard brake light doesn't work on my own Explorer so it has had its share of handbrake cruises.

 

[96eb96]

The parking brake on an explorer is quite weak, I'm surprised it can do any damage.

 

[koda2000]

I will certainly ask her about that. They drove about sixty miles before the thing gave up.
The dashboard brake light doesn't work on my own Explorer so it has had its share of handbrake cruises.

Driving with the parking brake on would certainly overheat the trans (not to mention the rear brakes). If your dash BRAKE light doesn't work, does the bulb light at bulb check? I think it should, but I can't say for sure with checking one of my own Ex's. If the bulb is working I've found that the switch, located at the rear of the parking brake mechanism, is typically to blame. This tends to be the weak point in the system and it is to be more problematic on vehicles where the parking brake is seldom used. It's partially because the switch get dirty or rusty and may also be due to the brass contacts can become dirty or corroded. I find a squirt or two of WD40 and some exercise will get the switch moving again and cleaning the brass contact with some fine sand paper will get it working like new. The switch provides the ground for the BRAKE light when the pedal is depressed, so it doesn't take much for it to not work.

I'll check one of my trucks for the BRAKE warning light at bulb check and edit.

Edit:
No, the warming light for the parking brake does not come on during the bulb check.

 

[Turdle]

Captain Hindsight says:

When driving through steep hills, you should turn off the overdrive with the button on the end of the gear selector lever.. This will allow the torque converter to lock.

A hunting torque converter climbing a hill will heat up fluid very fast. Better to sacrifice some engine rpm's.

Once you are on the downhill side the overdrive can be turned back on.