jthwan22

I had my 88 auto trans rebuild by Steve C. when I first got the car. The car will leak when it sit. It could be a week or 2 month before I see a red river of tears. I took it back to Steve 3-4 times but of course it does not leak at his shop. I think he moves the car everyday so it really not sitting. What could be the cause of this? Is there a detail instruction on tearing down auto trans? Dwayne hint, hint?

Landseer

Can you isolate the general location of the leak source?

The caps for the pistions, ie, the B2 piston, and the governer, have O ring seals, for instance. Leaking on one side vs other would be partially indicative of which.

The seals around the TC can leak. That would happen near the front.


I have lots of disassembly pictures if that will help you.

Dwayne does need to do a 35 chapter treatise on this, though, you're right! He would actually have reassembly pictures.

jthwan22

I am in Iraq now. When I get back I plan to clean up the area and put in UV dye and maybe that will help to pin point source of the leak.

90 S-4

They came from the factory that way, the converter fills up and over flows out the reservoir, do a
search here and you'll get a better explanation than mine. You just need to start the motor once a week
and it won't happen

Mrmerlin

the usual leaking areas are the cap and the rear reservoir tube seal,
and the pan gasket splitting from being overtightened and or it being and older part ( the pan seal)that also split from a normal torque of the pan bolts. pan gasket has been superceeded, I would figure that Steve C has the newer parts, as he does very commendable work.
Also you can check the grate for a leak or the cooler lines.
If its the grate then its prolly the front pump O ring,
if the lines are leaking then they should have new flex portions fitted also replace the portions at the crossover of the cats

GregBBRD

Almost 100% of the time, this is the o-ring leaking on the downshift cable, which you kept in the car, when the transmission got rebuilt. (I send a new o-ring with all my rebuilt transmissions, because this is very common.)

The torque convertor leaks down and fills the pan. This is the fist place the fluid can escape.

Simply replace the o-ring and you'll fix it. You car takes a "late" o-ring: 999 701 960 40.

GlennD

I had the same issue ... when it sat for 1 week, I saw the drops.

On mine, it turned out that the tranny pan gasket had split (very small split) and slowly leaked. I am surmising that over the week, the leaking transmission oil covered the metal in the area sufficiently to form drops going on the ground.

New gasket and not a drop since (1.5 years now) - even if parked 6 months (winter storage during the white months here).

Glenn

jthwan22

I do know it is not the trans pan gasket. it was replaced once at rebuilt, once when I brought the car back to Steve, once at Amoco.

I can't believe it is consider normal for it to leak by sitting for a week.

So how hard it to change these o-rings? I did the WP/TB myself but never did trans rebuilt.

Landseer

I just did it on an 89 that I installed in an 84 body.

I struggled with it for an hour. Then, I removed the pan and filter. That gave me access to the little lever and spring for the bowden cable. I could hold it with the left hand, unhook the bowden easily, replace the oring, and reconnect the bowden. Answer: easy if you remove the pan.

Landseer

Below are a couple pictures from an 84 and 85 to give you an idea. The 89 is similar, but I didn't snap pictures of it. Can if you really need to see it, but I'd have to disassemble. As usual, being a Dwayne wannabe but falling short, my pictures are not exactly what you need but will give you the basic idea.

Unlike the picture I show, your bowden O-ring will not fit a groove partway up the plastic bowden end like this one. Instead, your O-ring will be inserted into the hole in the trans and the 88 bowden white plastic end will contact it. Slightly different set up.

The little hook on the transmission is the same, though. Both the 84 and 88 bowden cables have somewhat similar female wire end fittings to accept the hook.

I would disconnect the other end of the cable in the engine compartment.

Then, clean all up around the car body and trans where the bowden enters the trans. Don't want dirt falling in.

Take the pan off the trans.

Then, squeeze the release and turn the white connector about 30
degrees to disengage Bowden cable from the trans.

With finger under the trans, on the kickdown lever mechanism, oppose the spring pressure.

Then, its easy to slip the hook out of the bowden female end.

Reach into the hole in the case and hook the O-ring with your finger or plastic hook of some sort, remove it. A little tricky.

Put new O-ring into the case. (have spare on-hand also, just in case, it is a little awkward)

Hold the spring mechanism, rehook the cable.

Seat white plastic end into the O-ring / twist the fitting back 30 degrees to lock it.

Replace pan.

Reattach cable in engine compartment.

Hope this helps.

jthwan22

Thanks guys, I will give this a try after I get back in the States.

Driving back to Steve takes 4 hours out of drinking beer each time.

GregBBRD

I was assuming that they had already determined that the pan gasket was good, since the transmission had been rebuilt...but indeed, any bad gasket, below that o-ring will cause a leak.

jthwan22

So I replace the trans pan gasket and filter before SITM. The pan gasket was split in the corner. I did not torque the pan bolts back to 8 ft/lb as per WSM. It is torque with 3 finger tip pressure and held with blue lock tight. No leak after long drive to and back from SITM. I think the 8ft/lb spec is too much if you go back and bring every pan bolt up to 8 ft/lb and will split the gasket.

terry gt

I had the same problem , after sitting for a week + the trans would leave a pool of fluid . Turned out to be the pan gasket , pounded the pan flange streight , new gasket , no leak .

jpitman2

Pan gasket leaks in 4 speeds can be caused by using the Original part no gasket which Porsche still supply, where MB have superseded it with a new version, for exactly this reason.....Only buy the MB service kit!!!
jp 83 Euro S AT 52k