Randy V

This is a recurring issue seen here, but I don't think I've seen a definitive corrective action.

Simply, when an auto trans 928 is parked undriven for several day (more than 5 days in my case), transmission fluid drains from the torque converter into the transmission case, then exits the breather vent located at the top of the case and leaks onto the floor.

Why?

Erik N

IIRC Podguy fixed this somehow.

Leon Speed

Just to switch from the other thread. I put the car on a lift, sprayed the pan and filler tank very well with brake clean so that all oil was gone, then left it overnight. In the morning I could see where the leak developed, which was the overflow hose. It leaked where it is connected to the tank. It is simply slid over a nipple on the tank.

jthwan22

I got the same problem for years. After many pan gaskets and it still leaks. I just have a large drip pan under the trans pan to catch the leaks. My 911 does not leak and the 928 leak like crazy.

SeanR

I've found that most of them do it. Sometimes it is the overflow hose, sometimes it's the cap that leaks. As to a fix, don't let the car sit for a few days.

heinrich

Randy, it USUALLY is the seals inside the trans. I have had this on just about every auto I have owned, and everytime it was a seal in the trans. I forget now what it is called, but it was white (front seal IIRC).

heinrich

I believe it's the 2 small sealing rings here #9, as well as #3

SeanR

When the torque converter seal leaks, you end up having drips from the bell housing.

byrdman454

I had a leak in that same area (TC seals) on the '85 I rebuilt for my nephew. After searching the archives on here, I decided to follow Bill Ball's and some others experience from old posts and put in some Trans-X with my oil change. After about a week or two, the leak dried up. It is now dry as a bone. I usually do not use these types of products, but it was either that, pull the transmission and replace the seals, or live with the leak. I decided to try it and it worked for this car. YMMV.

Randy V

Thanks guys.

Looks like it's not a simple fix.

GregBBRD

Randy:

90% of the time, the leak will be coming from the O-ring on the "shift cable". If the leak is coming from the middle of the transmission, on the right side, the odds of this being the problem go up greatly. Simply have someone replace this o-ring. Pretty easy fix.

The "real" problem, usually, is that the check valve for the torque convertor is no longer doing its job. This requires removal of the valve body to replace.

Randy V

You replaced that o-ring last time you had my car if you recall.



The problem must be the check valve, 'cause I get a trans fluid dump when the car sits for 5 days or more.

I get no other leak - only when the car sits for an extended period of time.

Chris

On my 91 I fixed this by getting the correct o-ring for the filler cap, I thought the fluid was coming from elsewhere but it is hard to see up there and the fluid goes everywhere once it comes out.

James Bailey

The failed check valve is what causes the fluid level in the transmission to be too FULL and look for a way out....like a poor seal on the fill cap or bad o-ring or out the breather hose.....

User 4221

Or swap in a 5-speed