pdub

To all my helpful and friendly fellow Rennlister's !!

I have a leaking tranny issue. Upon filling the tranny to full, doing a test drive and putting it up on Mr. Carter's rack (thanks Don!!) we noticed most of the fluid was pooling on the passenger side of the tranny by the resevoir. We couldn't really see an obvious leak, but when we kept looking it seemed that the brass looking retainer ring in the picture was the problem, perhaps?
Note, the pan gasket was changed within the last 30 days.

Appreicate any and all help!!

Paul

fonetico

Have the exact same problem on my '90 S4.
I understand the system is pressurized so my next option is to replace the rubber seal in the reservoir cap.
It was interesting driving around with no fluid in the transmission, with the car selecting gears at random, but really frustrating after I'd changed gasket, filter and fluid to find the transmission still leaking copious quantities of fluid.

pdub

Fon
Did you notice seepage aroundd the brass retaining ring as well?

fonetico

Paul,
I suspect you deserve an elaboration of one of my subtle ironies of life.
I've lived with this issue for some months now, never sure where the fluid was leaking from. I have to confess to even using silicon bathroom sealant in an attempt to pinpoint the exact place.
All to no avail.
So I changed the gasket. Still no joy.
In desperation, I stuck a latex glove over the filler and screwed on the cap. After three days, no leakage.
The new seal arrived today and I've substituted my glove improvisation. I'll check it in a couple of days to determine whether that was the culprit.
The subtle irony in all of this is the banality of the solution. But, for God's sake, how do you establish where the leak is when the whole unit is covered in fluid?
Try the simple solution first?

Don Carter

Paul,

Hopefully someone can chime in with some information about that sensor, how to remove it (takes a very large wrench or socket) and how much fluid loss there is when removing. Should be fairly simple to replace the seal, o-ring or crush washer that seals it.

Glad to hear the volume of leakage is less after topping it off. That seems to happen a lot for some reason. I had a puddling leak on my 89 when I got it and the fix was to fill it up. Makes no sense.

We can get it up in the air again, week from Friday if you want and slap some gauges on the AC to try to see what's going on there.

pdub

Well after more tries and fails my tranny guy has told me that the fluid from the TC is draining back into the reservoir and coming out the top so his explanation is to R/R the valve body(which is exactly what Sean thought it was last we spoke). Has anyone else had this happen ? Pretty pricey $650.

GregBBRD

That timing retard sensor simply unscrews out of the transmission. There is no gasket, o-ring, or any other form of sealing....it seals against the case.

I apply a very thin layer of Drei Bond on the surface that touches the case...being careful not to allow any excess to squeeze inside the transmission.

GregBBRD

BTW....the reservoir and fluid in the pan are not under pressure.

GregBBRD

The most common leak, on the right side is from the O-ring that seals the plastic end of the kickdown cable into the transmission.

Almost all of the transmissions will allow the torque convertor to leak it's fluid into the pan, after a week or so of sitting. (Anything faster than that probably needs to be repaired.)

At any rate, the first place that fluid escapes is generally from the aforementioned O-ring.

pdub

Greg
Thanks for the info. I Replaced the entire reservoir with new o-ring, so don't think that's it. I'll double check with my tranny guy. The guy is very familiar with this transmission as he has several lying around his shop. I am just trying to find the end of this tranny tunnel!

If not the owing then could a valve body R/R be the answer. I know it's hard to tell from just this post without seeing the tranny.

Rodrv6

My 88 S4 was leaking from the rubber tube that goes from the top of the plastic reservoir to the case. A new piece of rubber hose fixed it.....

pdub

Greg
Forgot to mention that the washer around the thrust pin for the kickdown cable was replaced as well. Think my tranny must look like Swiss cheese!

Schocki

Here is what you find inside. The valve with three differnt o-rings. The small o-ring inside the tranny is exposed to the highest heat from the ATF. This o-ring hardens the most and leaks.
Replace the o-rings and use some sort of sealant on the outside. Since it is metal to mteal I would go wtih Loctite 574.
Greg can probaly tell it it's safe to remove the valve and insert it again while brake band B1 is still in place inside. Replaced everything when I repaired my reverse in the GTS. You don't want to pull everything out just to find out that the thrust pin is not engaging into B1 anymore

Here is my B3 write-up: https://rennlist.com/forums/928-foru...ement-diy.html

pdub

Schlocky
Thanks I did that gasket with Don C last year. It's a bear to stop the tranny from leaking once she starts. Hoping to hear back tomorrow on mine.

pdub

fingers crossed.