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Leaking Transmission Fluid

Help! My car is on the lift, and everyone is fighting…I had the transmission fluid changed, and afterwards, it began leaking. I took it back, and was told the transmission cover gasket was leaking…I let them replace it…they said that there may be more than one leak - to keep a check on it. When my check engine light came on I checked the transmission fluid, because it had been leaking again…the level was a little high, but I thought I had maybe checked it wrong. I took it to a different repair shop, and they found that the seal between the engine and transmission is leaking…they will have to drop the transmission to repair this. They said that the fluid was in the normal range. Could overfilling with transmission fluid blow out the seal/o rings/gasket? They say the tech who originally “changed the fluid” is responsible for this problem…Help!

I am trying very hard to visualize a seal between the engine and transmission. Could you give some details (make ,model,year,engine type,trans type).

Maybe a technical name (listed on the repair order) for this seal.

Overfilling your transmission won’t damage any gaskets. The most common source of leaks would be the pan. If the pan was dropped and then put on not using proper torque specs for the pan bolts, that could be your problem. The mating surface of the pan will be bent if the bolts are put on to tightly and will leak. Other than that I can’t think of any way a leak could be caused by a trans fluid change. Go to a different shop and get a second opinion.

The car is a Volvo S40 (2000), automatic transmission. I do not have a repair order in writing…yet. They called me, and told me what they had found…by the time I got to the dealership the service department was closed…I could see the car up on the lift through the windows…since they were closed for Thanksgiving today, I plan on going to take a look at it tomorrow.

The front transmission seal is a round seal with metal on the outer diameter and rubber on the inner diameter. It is driven into the front of the transmission behind the torque converter, metal to metal as an interference fit. The rubber seals the transmission’s rotating output shaft. Its name is Fred. Get the picture?

Replacement requires pulling the tranny away from the engine. It’s the only way to get to it. Unfortunately it is labor intensive.

How much is it leaking? A quart a month, week, or day? If the first, you can buy a lot of quarts of fluid for the cost of this repair. Two drops on your garage floor will spread out to a couple of inches in diameter. Looks like a lot, but it really isn’t.

I don’t see how changing the fluid could have caused this seal to leak. A fluid change could cause the pan gasket to leak IF the pan were removed during the procedure. Was it done as a “flush and fill” with a machine pumping new fluid into the transmission’s cooling lines, or was it done the old fashioned way by removing the pan? That way only changes PART of the fluid.

First of all, just how high was the level?? Overfilling is not going to raise pressures and cause the pump seal to “Blow” out. The pump could be “venting” It is quite common for a pan gasket to leak after the pan has been removed. Pans need to be perfectly straight when reinstalled. Prying the pan off during service will cause it to leak if not careful so I can see it leaking after the service. If replacing the pan gasket again cured that leak then I would first just clean up the trans and get the fluid to the proper level. If the pump was just venting then the leak should stop from the bellhousing area. Watch it carefully for a couple of weeks because you might still have some residual oil in the bellhousing area that will drip for a short time. If you notice the trans still leaking from the bellhousing area then the trans probably did have 2 leaks and it would be time to remove the trans and replace the front seal and bushing. Let us know how it comes out.


I went to look at the car today. It is leaking from the front seal area. The pan gasket (which was replaced) is not leaking. They have left it up on the lift…there was a little puddle of transmission fluid under it…they said that when the car is idling it drips out continually (they did not demonstrate this for me). They said the car is undrivable…that is interesting, because I drove it there. The Volvo mechanic said that they do not “fill and flush” S40"s…I asked why not, and he said they don’t need to…that they don’t have any problems with the transmission on this model. I asked what happens when they are mechanically flushed…he said he didn’t know…they just don’t do it. BTW…this car does not have bellhousing…the design has been changed to one piece. The mechanic said he would be very angry, if this was his car, and he indicated that the shop that originally changed the transmission fluid is responsible. He said he didn’t know what had happened…sometimes bad things just happen, but that IF I had had the transmission fluid changed at the Volvo dealership, they would take responsibility for repairing the leak… I also do not know if they used the correct fluid…

The only thing I can add is that it sounds like the torque converter (front pump) seal is leaking.
If so, I don’t see a fluid change, pan drop, or even a flush as causing this seal to leak.

If the gasket that was used on the pan was of the cork variety it’s quite possible that gasket could be leaking. I refuse to use a cork gasket for this very reason; it’s strictly rubber or cellulose.

The reason they tell you the car is undriveable is because with a steady transmission fluid drip it would be very easy for the car owner to dismiss it and keep on motoring. This could lead to a fried transmission very shortly and finger pointing over who did what or who was going to be at fault for whatever.

As to what you’re being told by the mechanic about “being angry if this was his car” and they would “take responsibility for this leak if they had changed the fluid” I can only say - utter BS on their part.
They’re simply trying to one-up the previous shops and portray them in a bad light; and believe me, this is not that rare a thing to occur.
I bet Transman knows what I’m talking about! :slight_smile:

I agree…it just doesn’t make sense…all I know is that I didn’t have a problem before I had my transmission fluid changed.

The gasket is gray in color…if that may indicate what it is made of…it looked kind of spongy (maybe rubber or plastic) It looked dry and oil free.

Yeah…I know…they have me in the middle, and they are trying to make me angry enough to get really aggressive against the original repair shop…I am like a ping pong ball - running back and forth…it is a really long story, and I don’t think that is what this list is all about…

I really appreciate all of the technical information that everyone who responded has given me…I have learned quite a bit about the transmission, and I have been able to ask reasonable questions…Thank-you so much!

If the torque converter seal is leaking I see no way on earth they’re responsible for this. The seal is located between the converter and the transmission. To tamper with this at all means they would have to remove the transmission from the car.

Here’s a couple of possibilities that could cause this. (assuming converter seal)
Clogged or defective transmission vent. When the fluid gets hot it expands. If the vent is inoperative fluid will try to force out somewhere.

Another could be a leaking transmission fluid cooler (inside the radiator). The cooling system is under pressure when hot, and especially if the transmission vent is faulty, maybe the cooling systme is pressuring up the transmission internally and forcing fluid out past a seal that may not normally leak.

I’ll reiterate; what you were told by dealership about being angry, standing behind it, yada, yada, yada, is bunk.
I GUARANTEE you that if a converter seal started leaking after a simple transmission fluid change they would not for one minute stand behind that for free.
Nor should they.

This is an interesting piece of information! I didn’t mention…the “check engine light” came on…which was the reason that I took it to the Volvo dealership…they said that the reason the light came on, is that the thermostat has been sticking, and that it needs to be replaced (to the tune of $235.00…also my “software” needs to be “updated”…another $163.00). I had not noticed the car overheating…but then again, I do well to look at my gas gauge… Since I did know that the transmission fluid is cooled by running through the radiator, I asked if this could have caused enough of a problem with the thermostat that this is what the software indicator “picked up”…in other words, I question if there is a real problem with the thermostat…the service manager just said, “that’s an interesting question”. I didn’t realize how “interesting” that possibility might be.

So…should I ask them to check the water in the radiator for transmission fluid?

Tell me about this “vent”…where does it vent to? Does excess transmission fluid actually drip out of the car through this vent?

Could someone please advise me…they put dye in the transmission fluid in order to see the leak. Does this fluid need to be drained, and refilled with new fluid before driving the car? They said that the car was “undrivable”…it wasn’t when I drove it into the dealership.

The dye wont hurt the transmission if thats what you are asking. From what I have read they are saying its undrivable because you have a steady leak from the bellhousing area which is most likely a front pump seal and/or pump stator bushing. I would tell you its undrivable also because its very dangerous to drive the vehicle in this condition. As the fluid gets lower and lower, the transmission will start slipping. Once it starts slipping it is destroying itself. Get it fixed before driving it.


A thermostat can also cause an engine to run too cold if the T-stat is stuck wide open all of the time. Running too cold can lower the fuel mileage and possibly cause the Check Engine Light to come on.

The transmission vent is just that; an opening to the atmosphere. Think of a rooftop vent that allows hot air to be expelled out of the attic; although fluid should not be expelled. The odds of the vent being the problem here are pretty slim, or near zero.

Odds are the T-stat could be replaced elsewhere for less money and as to the question of whether the T-stat is bad I have no idea.
What I would really be concerned with is your statement that you “do well to look at the gas gauge”. Not paying attention to temp gauges and dashboard warning lights has been the cause of (the majority IMHO) of engine failures.

As mentioned by Transman the dye hurts nothing and a steady fluid drip in the area around where the transmission mates to the engine usually means a torque converter seal.

They are holding the car hostage up on the lift…everyone is lying to me…back and forth between service departments. I am thinking about asking them to lower the car, so I can crank it and see how much it is leaking when idling, and if it doesn’t look too bad…I’ll drive it a few miles to another shop. Otherwise…tow it. Right now, I am so upset with all of this bickering that I don’t want to pay these guys to fix the car. This has not been handled well…everyone should have sat down together, and talked this all out to resolve this problem. I am tired of being in the middle. I need some control over this situation.

As a follow-up…my car was finally repaired…they replaced the front pump transmission seal, and the rear main oil seal. They also replaced 4 stripped subframe bolts. I picked it up on Wednesday, and I noticed that when I cranked it, it idled rough…I thought it was going to cut off…it just seemed strange…but I had been driving a Grand Jeep Cherokee for several weeks…big difference. Anyway…the second time I cranked it, the check engine light came on, so I took it back on Thursday. They found that they had failed to hook up a hose, which was causing a problem with it idling. This made a big difference, and the car seemed much more “normal”. Today, I was driving it, and I stepped on the accelerator to get out of the way of a fast moving SUV, and the turbo did not kick in…is the turbo connected into the transmission?..could this be caused by the transmission removal and replacement?

The front pump seal you mention is also the same as the torque converter seal and as mentioned, this seal is not accessible without dropping the transmission.

Question. Did you buy this car new or do you live in a northern rust belt state (MN, OH, etc)? The reason I ask is because you mention 4 stripped subframe bolts which is very odd.
No way should this occur unless they were rusted to oblivion or someone has had the transmission out before and stripped them due to being ham-fisted.

The turbocharger is not connected to the transmission. While it’s very difficult to tell what’s going on here, is it possible the sluggishness you feel when the turbo did not kick in is actually the transmission not downshifting as it should during hard acceleration and this is not a turbocharger problem at all?

If the problem is legitimately in the turbocharger system, and this problem was not present before, then the problem could be an intake boot clamp loose or something like that. This would allow the intake to lose boost pressure when you’re trying to accelerate hard.

Wished I could be of more assistance and hope this helps some.

I bought the car used in 2003. It had 50,000 miles on it…it now has 81,000 on it. The lady who was the original owner had a local address (Raleigh, NC). I have no idea what the stripped bolts indicate.

Thanks for the information…I have heard that the turbo can be very complicated. I used to step on the accelerator and take off like a rocket…it came in handy, to get out of the way!. I don’t use it very often. I guess I need to drop back by the service department and see what they say.

While I can only theorize here, considering the vehicle had 50k miles on it when purchased it’s possible that the transmission could have been replaced or repaired under warranty at some time in that 50k miles.

Whenever a transmission comes out the front pump seal should ALWAYS be replaced and many times this is not done. If someone got a bit careless when reinstalling the transmission the original seal could have become dislodged a bit or damaged. Eventually it is going to give up because of this.

The stripped bolts could be a sign the transmission had been removed at some time and considering all 4 were stripped I would theorize that someone installing them during this transmission reinstallation probably tightened them too much with an air wrench. If only 1 bolt was damaged I would say it had been cross-threaded but with 4 being damaged this would point to someone being too aggressive with the air wrench and causing the threads to pull. (Pull means they’re not stripped but are distorted outwards. Either way, they’re bad.)

You might post back after seeing what they have to say about this current sluggishness problem. Maybe we can at least tell you if what you’re being told is legitimate or not.

Maybe I should try to locate the original owner…I’m just curious…if the transmission has been previously repaired…that would answer a lot of questions. It is ironic though…the Volvo mechanic said that they “never have problems with the transmission in the S40”… :-o

Thank-you so much for your input!