Auto Trans Pan Gasket

[DeLorean03]

So I have a question:


Is there any kind of a composite/rubber replacement for the auto transmission pan gasket. The cork one just seems almost inferior to me. I have had a new cork trans pan gasket for about 3 years, and I think it is starting to leak. The gasket literally sticks out from between the transmission body and the pan; it just doesn't seem to be a good fit, and cork by nature is going to soak up only so much liquid before it begins to seep through and leak.

Whether the cork gasket truly is the source of my leak is not my question. My question: is there ANY kind of upgrade from the cork gasket to something a bit more modern? Do any of the vendors use a rubber/composite replacement?

For those who are interested as to why I ask, my passenger side has a nasty lil' leak. The top of the transmission is bone-dry. The driver's side is bone dry. The passenger side, particularly around the vacuum modulator/shifting cable has a good amount of transmission fluid covering everything. Sitting still with a flat cardboard box underneath it, I get 2 different puddles almost right next to each other that look about 2-2.5 inch diameter overnight. Keep in mind the viscosity of transmission fluid and the fact that one drop seems to seep for miles as well as how well cardboard seems to soak in fluid (making 1 drop seem like the size of a quarter). Also, the transmission does not leak when the car runs, only when it sits.

[DMCMW Dave]

So I have a question:
Is there any kind of a composite/rubber replacement for the auto transmission pan gasket. .

Not that I've seen. If the cork is sticking out the gap, the screws are too tight.

I have heard of (but not tried) using "The Right Stuff" sealant with no gasket at all. Do this at your own risk. . . .

Actually in your case, you may need to replace the shift cable. There is a small rubber seal inside the transmisson end that seals fluid from around the cable that goes to the shifter. They fail ALL the time. The leak will appear around the cable where it goes into the trans, and the real giveaway on this one is oil inside the frame under the accumulator.

Replacing the cable is a bitchy job though. Access to the cable at the trans is hard, and the outer fitting wants to come loose before the inner fitting. If you remove the outer fitting the connection inside will drop and you will be taking the transmission apart to line it all back up again. If you unscrew the center fitting and LEAVE IT IN PARK you can make the connection without taking the pan off etc. Hard to explain.

[David T]

Properly installed the cork gasket is fine. That's the "rub". Overtightening the bolts bends the pan and it will leak. The shift cable can be a source of a leak. Rob Grady sells heat shrink tubing to seal the ferrules so you don't get fluid leaking out of it. The seal for the vacuum modulator can leak. The front pump can leak. The "O" ring on the dipstick tube can leak. When this stuff leaks it hits a rib and can run around the case and drop in a different spot depending on how level the car is. You need to clean the case and watch for where it starts leaking from. Overfilling will also make it leak. As with all British cars, when they stop leaking it is time to check the fluid level!!!!!
David Teitelbaum




Not that I've seen. If the cork is sticking out the gap, the screws are too tight.

I have heard of (but not tried) using "The Right Stuff" sealant with no gasket at all. Do this at your own risk. . . .

Actually in your case, you may need to replace the shift cable. There is a small rubber seal inside the transmisson end that seals fluid from around the cable that goes to the shifter. They fail ALL the time. The leak will appear around the cable where it goes into the trans, and the real giveaway on this one is oil inside the frame under the accumulator.

Replacing the cable is a bitchy job though. Access to the cable at the trans is hard, and the outer fitting wants to come loose before the inner fitting. If you remove the outer fitting the connection inside will drop and you will be taking the transmission apart to line it all back up again. If you unscrew the center fitting and LEAVE IT IN PARK you can make the connection without taking the pan off etc. Hard to explain.

[DMCMW Dave]

sells heat shrink tubing to seal the ferrules so you don't get fluid leaking out of it. The seal for the vacuum modulator can leak.

I have never understood that repair. If the seal inside the cable leaks, it will run out of that fitting. If you shrink-wrap the fitting the oil comes out the other end and ends up inside the frame.

The only real fix for a leaky cable at this point is to replace it. The part that fails is a tiny o-ring that can't (easily) be replaced by itself as it is installed on the shift cable before the end fitting is crimped in place.

[DeLorean03]

Ok, last question I got for a while - I think.

I've noticed something my transmission is doing. Say I'm in a parking lot and I'm just "coasting" in 1st. Sometimes this will happen, and I'll go to give it gas, and the car will act like it's in neutral - rpms go way high then as the rpms come down it'll catch. It is ONLY when going at "coasting" speeds. The transmission is solid other than that. It upshifts fine at normal driving speeds, downshifts fine at normal driving speeds, passing gear engages strongly, all the positions on the gear selector seem to be responsive - the only time it acts funny is when I do what I described above, and it has to be done JUST right - the right speed with the right amount of RPMS, else it will catch and act as it should in normal operating condition.

I've noticed that if I gently press the brakes to slow the car down and then give it gas, it will never do what I described above. It will only do it if the car is coasting.

I'm thinking there's something faulty with the vacuum modulator. I plan on putting a pressure gauge on the transmission this weeked and going through the pressure tests per the workshop manual. It is definitely not the governor as the car did this Dec 2011, and I had DMCH's digital governor installed Spring 2012. This transmission had a complete internal rebuild in terms of clutches,seals, and gaskets back in Nov 2003, as well as a new torque converter and vacuum modulator. Doesn't mean one of these aforementioned things didn't break - just giving everyone a history of this transmission's service. Filter was cleaned in Sping 2012.

[David T]

Do all of the external On-Car adjustments including the gearshift. It may be you are not completely in Drive. Check the fluid level. You may have to take the car to a transmission shop and have it power flushed, a spool valve may be sticking in the valve body.
David Teitelbaum




Ok, last question I got for a while - I think.

I've noticed something my transmission is doing. Say I'm in a parking lot and I'm just "coasting" in 1st. Sometimes this will happen, and I'll go to give it gas, and the car will act like it's in neutral - rpms go way high then as the rpms come down it'll catch. It is ONLY when going at "coasting" speeds. The transmission is solid other than that. It upshifts fine at normal driving speeds, downshifts fine at normal driving speeds, passing gear engages strongly, all the positions on the gear selector seem to be responsive - the only time it acts funny is when I do what I described above, and it has to be done JUST right - the right speed with the right amount of RPMS, else it will catch and act as it should in normal operating condition.

I've noticed that if I gently press the brakes to slow the car down and then give it gas, it will never do what I described above. It will only do it if the car is coasting.

I'm thinking there's something faulty with the vacuum modulator. I plan on putting a pressure gauge on the transmission this weeked and going through the pressure tests per the workshop manual. It is definitely not the governor as the car did this Dec 2011, and I had DMCH's digital governor installed Spring 2012. This transmission had a complete internal rebuild in terms of clutches,seals, and gaskets back in Nov 2003, as well as a new torque converter and vacuum modulator. Doesn't mean one of these aforementioned things didn't break - just giving everyone a history of this transmission's service. Filter was cleaned in Sping 2012.

[David T]

I understand and agree but it works. Hard to argue with success! And a lot less expensive than replacing the cable!
David Teitelbaum





I have never understood that repair. If the seal inside the cable leaks, it will run out of that fitting. If you shrink-wrap the fitting the oil comes out the other end and ends up inside the frame.

The only real fix for a leaky cable at this point is to replace it. The part that fails is a tiny o-ring that can't (easily) be replaced by itself as it is installed on the shift cable before the end fitting is crimped in place.

[DeLorean03]

Do all of the external On-Car adjustments including the gearshift....
David Teitelbaum


Is there somewhere in the workshop manual where this is clearly labeled pr expanded on? I don't know what "all ...adjustments" entails exactly...

Thank you (: !

[Nicholas R]

...it has to be done JUST right - the right speed with the right amount of RPMS, else it will catch and act as it should in normal operating condition.


Haha, when I read this, I immediately thought of, "Doctor, it hurts when I do this;" "Well then dont do that!"

Joking aside though, yea that seems a bit weird. Fluid level? Though it seems like if it was fluid level, it wouldn't take such precise circumstances.

[David T]

Start on G:04:01 and finish on G:05:03
David Teitelbaum





Is there somewhere in the workshop manual where this is clearly labeled pr expanded on? I don't know what "all ...adjustments" entails exactly...

Thank you (: !

[TripleZeroFilms]

To jump in on an old topic here, I've got a pretty nasty leak around my Vacuum Modulator. Thing is, I can't tell whether it's the seal around it that's leaking or the modulator itself (is that even possible?). Is it possible to over tighten the modulator in and cause a leak, or is it a one-size-fits-all deal?

[Dangermouse]

Is there any kind of a composite/rubber replacement for the auto transmission pan gasket. The cork one just seems almost inferior to me. I have had a new cork trans pan gasket for about 3 years, and I think it is starting to leak. The gasket literally sticks out from between the transmission body and the pan; it just doesn't seem to be a good fit, and cork by nature is going to soak up only so much liquid before it begins to seep through and leak..

Old thread I know, but cork is impermeable so it's not going to soak up anything.