I'm attempting to chase the source of a small pool of reddish-brownish fluid that showed up on my 2005 S-Type 3.0's belly pan when I dropped it yesterday. From my JTIS CD in the 2004 S-Type ZF 6HP26 transmission's "Diagnostic Strategy" section, I just found this statement:

"A fluid level that is too high may cause the fluid to be aerated due to the churning action of the rotating internal parts. This will cause erratic control pressure, foaming, loss of fluid through the vent tube, and possible transmission damage...."

Wow! A vent tube in the 6HP26! Who knew? So much for "sealed units"....

So where exactly is this vent tube, and where exactly does the vented fluid show up?

 

Awesome find Jon.
Now where the hell could it be........

 

Er, this isn't news. Suppose you knew where it is, then what?

 

Had this in a pdf I downloaded.

 

Er, then I would not have asked the question.....


In all the ZF threads THAT I have read over the years, I cannot recall one that has mentioned an "overflow" tube. I guess I really need to download all the JTIS and blah blah manuals and read the damn things after all these years!

 

Grr, that's not what I meant!

 

Happen to have one sitting in the garage, and yep, there is a tube there. Never paid it much notice before.

And guess what, it's PLASTIC. Ripe for bashing when installing the transmission, I'd say.

 

I e-mailed Klaus at The CTSC yesterday and asked him. He replied that the vent tube sits on top of the ZF unit. Charlie's photo confirms it. So it appears that any vented fluid would dribble down the U.S. driver's side of the ZF housing and probably wind up collecting on the U.S. driver's side of the bottom of the ZF oil pan, then dripping off to the pavement below. From what you can see of your crated ZF unit, Charlie, do you agree?

That probably rules out my current belly pan wetness coming from my ZF's vent tube....

 

I don't think so, it's going to vent into the bell housing, (for some reason) dribble down and run out the hole at the bottom centre.

 

I think you're right, Norri. I should have paid more attention to the drawing than to the photo....

It still looks like the dribbled fluid wouldn't be able to make its way to the belly pan, though. Thoughts, anyone?

 

So theoretically us DIYers can overfill and any excess will basically blown out to the pavement, interesting.

 

And as the drawing points out, the vented fluid can be mistaken for a leak in the ZF unit....

I assume that fluid can be vented only when driving. You don't think that the ZF can vent fluid just sitting in the driveway, do you? As quirky as these things are, I'm at the point where I'll believe almost anything now....

 

I'd surmise from reading this that it's only going to happen when the box is working but it will probably drip for a while while standing.

I don't recall how far back the pan comes, is the hole clear?

 

I'll find out if that hole in the bell housing (if it is indeed a hole - from a line drawing you never know) is clear of the belly pan when I climb underneath the car again a little later this morning. We finally have our sunshine back today so I hope I can figure out the great fluid mystery....

 

I'm wondering how Jon89's car could have overfilled its ZF box after all this time, such that it's started to dribble the excess.......

Must be a lot hotter there than I think!

 

I do not believe that we overfilled my S-Type's ZF when we did the drain-and-fill back in early November at Rick's home. I believe that Rick, Wayne, and I got it right on the nose. After we finished up, we even went back and pulled the fill plug again to go through the final top-up procedure one more time just to make sure. Once again, we waited for a slow fluid dribble out of the fill plug hole within the correct temperature range according to Rick's thermometer gun....

I'm just looking for all potentially plausible causes for the fluid I discovered sitting in my belly pan a couple of days ago when I dropped it to take a close look at my HVAC compressor (I'm also experiencing A/C issues). It could be coolant, but my coolant expansion tank is 100% full where I always keep it. It could be power steering fluid, but my power steering fluid reservoir is 100% full where I always keep it. Or it could be ATF, and without a dipstick who the hell knows whether my ZF unit is still carrying its full 10-litre capacity of fluid....

 

I believe you. That's why you don't have any oil out of that top vent.

If you clean the place where you found the oil does it get more? If it does, compare with the PAS oil (which is Dexron III, I believe) - probably by (ready for it) taste if touch/smell/etc don't reveal what it is.

 

I dropped my undertray recently to change oil, and found fluid in it as well. Not motor oil, or ps fluid. It looked to be ac compressor oil.

Just a side note, my 2006 Mustang has a 5R55S transmission of which has a vent tube to the bellhousing, where, if the fluid were to expand, it would overflow through the vent tube into the bellhousing and eventually drain to the ground below.

I have fitted a hose from the vent up to a "catch can" mounted on the firewall. Overkill, but was a good idea when I brought it to the track.

Excessive heat, overfilling, and or hard shitfs from wot, but I bet what you're seeing is compressor oil from the aircon system.

 

I believe that our S-Type compressor oil has green dye in it, therefore producing a "green slime" when the seals fail. Some of us long-time owners have seen this before on our factory compressors before we replaced them when they failed. My replacement compressor is bone-dry now with no signs of green slime. It was installed in early June 2010, so maybe it has indeed failed. But because the pooled fluid in my belly pan was a reddish-brownish color, I don't think it came from the compressor. Anything is possible, though....

Time for me to quit speculating on where this fluid came from and get out there again with my flashlight and some rags. The sun is high in the early afternoon sky now giving me maximum outdoor light, I've finished most of the other chores I had planned for this morning, so let's go see what I can find poking around underneath the car....

 

Jon I am betting you need to change the P/S pump. I fought this on my 2005 STR for about 16 months. Trying everything I could think of including buying a boroscope to closely inspect the area.

I never really had the P/S fluid go down in level but it must have. The P/S pump is so jammed in to the engine I could not ever get a clear view but I did have some fluid in that area.

Can you inspect the bottom of the P/S pump and hoses and report back if they are damp or not? Just a guess here!

Very interesting about the vent too. I learn something new everyday on this forum!
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