Tranny leak...seal or vent tube?

[Ed_Strong]

My 2000 Windstar LX 3.8 with less than 35K miles, started leaking tranny fluid after my brother drove it hard thru steep highway inclines 2000miles ago (he didn't abuse it by the way) before handing the van to me.
I've read a few posts here of similar leak issues after driving hard on hilly terrain, making the fluid boil and come out the vent tube, but he is insisting the fluid is coming out the main seal between the converter and fluid pump.
He owns a fleet of Ford E-conoline vans and an Expedition and they've all failed on him from that seal.
Is the Windstar tranny prone to failing on this seal also?
I can't tell if the fluid is coming from the vent tube or the seal since I can't find the tube and the seal is inside.
The van seemed to start leaking after it ran at or over 60MPH for long distance and it's not a big leak, but today it didn't even go over 45MPH for less than 15 mins and it also started smelling... something it didn't do before.
How can I tell for sure where the fluid is coming from?
If that seal needs to be replaced, how hard would that be?

[chasealley]

Well, I have no idea on this one but I can help you with the vent tube.

When we changed the fluid on my 2001 we were having a hard time getting a reading on the dipstick. So dang frustrating. On a whim I went to alldata (laptop on workbench) and found a TSB for the vent tube getting plugged and preventing air from getting in and giving a false reading (and hard shifting).

In short, the vent tube is on the top of the trans and right behind the shift linkage (toward the driver). On mine it is a tiny black rubber cap and that's about it. To top it off, mine fell down and blocked the vent tube (that's what the TSB was about). It had to move a whole 2.5 mm to cover the tube I'm sure.

If you are leaking from there you'd see a stream of fluid coming down from the top of the trans. Now, for the 2001 the fix for the TSB was to replace it with an older version. How old? I don't know. What does it look like? Haven't got mine fixed yet, but apparently the vent tube cap has a couple chambers in it.

I don't know, but could climbing some hills with the vent cap blocked cause a similar problem as the TSB's hard shifting and erratic fluid level? I'd check that cap after you locate it before you remove it to see if it had fallen down.

Other than that, I'm sure someone while have some better ideas

[garync1]

If the fluid is bad it may be foaming. I have mine changed at the dealer about every year. Although this year I have not had it done because the fluid is still clean looking. But after the first change it seem to get dirty again most likley because its hard to get all of it out even with the fluid exchange system they use. It runs about 156.00 but on hard use if your fluid is black it need to be changed. ASAP. so in the 3 years I have had it in been done twice. Mine is a 2001 with a little over 90,000 miles on it. The tranny started slipping when i first got it I was lucky that only the fluid needed changing. Been tranny been fine ever since knock on wood.

[Ed_Strong]

When I checked the fluid level today, after driving for about a ½hour, there was no foaming on the dipstick and it looked good in color. But it smelled burned to me. But I don't know what burnt tranny fluid is supposed to smell like, so I'm not sure it is actually burnt.

[garync1]

Originally Posted by Ed_Strong

When I checked the fluid level today, after driving for about a ½hour, there was no foaming on the dipstick and it looked good in color. But it smelled burned to me. But I don't know what burnt tranny fluid is supposed to smell like, so I'm not sure it is actually burnt.

I know the new fluid smells like bad body odor .. no kidding. Is it still leaking.
Maybe a seal around the sensor is bad.

[Ed_Strong]

Well today I was able to do the tranny fluid flush and filter change and the van runs and shifts so much better and it really responds better to throttle. I found out this van was running on Mercon/Dextron III and it felt really slugish and slow at accelerating, but now I can really tell the difference.
I used all 15quarts of MerconV and I hope I was able to get all the old fluid out of the system, I think I must have done so.
So it got me thinking that maybe the old incompatible Mercon/Dextron III was boiling under stress and expanding causing it to leak out. Hopefully it was thru the vent tube and not thru any seals. I'll keep an eye on things and see if it stops leaking from now on!
Thanks again for the help guys!